E-text prepared by Ronald Calvin Huber, while serving as Penobscot Bay
Watch, Rockland, Maine, and Joseph E. Loewenstein, M.D.



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Contributions from the Biological Laboratory of the U. S. Fish
Commission, Woods Hole, Massachusetts.

MARINE PROTOZOA FROM WOODS HOLE.

by

GARY N. GALKINS,
Department of Zoology, Columbia University.

_Bulletin of the United States Fish Commission_ 21:415-468, 1901






Comparatively little has been done in this country upon marine
Protozoa. A few observations have been made by Kellicott, Stokes, and
Peck, but these have not been at all complete. With the exception of
Miss Stevens's excellent description of species of _Lichnophora_ I
am aware of no single papers on individual forms. Peck ('93 and '95)
clearly stated the economic position of marine Protozoa as sources of
food, and I need not add to his arguments. It is of interest to know
the actual species of various groups in any locality and to compare
them with European forms. The present contribution is only the
beginning of a series upon the marine Protozoa at Woods Hole, and
the species here enumerated are those which were found with the algæ
along the edge of the floating wharf in front of the Fish Commission
building and within a space of about 20 feet. Many of them were
observed in the water and algæ taken fresh from the sea; others
were found only after the water had been allowed to stand for a few
days in the laboratory. The tow-net was not used, the free surface
Protozoa were not studied, nor was the dredge called into play. Both
of these means of collecting promise excellent results, and at some
future time I hope to take advantage of them.

My observations cover a period of two months, from the 1st of July
to the 1st of September. During that time I was able to study and
describe 72 species representing 55 genera, all from the limited
space mentioned above. In addition to these there are a few genera
and species upon which I have insufficient notes, and these I shall
reserve until opportunity comes to study them further.

I take this opportunity to express my thanks to Dr. Hugh M. Smith
for many favors shown me while at Woods Hole.

In dealing with these marine forms from the systematic standpoint,
two courses are open to the investigator. He may make numerous new
species based upon minor differences in structure, or he may extend
previous descriptions until they are elastic enough to cover the
variations. The great majority of marine protozoa have been described
from European waters, and the descriptions are usually not elastic
enough to embrace the forms found at Woods Hole. I have chosen,
however, to hold to the conservative plan of systematic work, and to
make as few new species as possible, extending the older descriptions
to include the new forms.

The different classes of Protozoa, and orders within the classes,
are distributed more or less in zones. Thus the Infusoria, including
the Ciliata and the Suctoria, are usually littoral in their habitat,
living upon the shore-dwelling, or attached, water plants and upon
the animals frequenting them. It is to be expected, therefore,
that in forms here considered there should be a preponderance of
Infusoria. Flagellated forms are also found in similar localities,
but on the Surface of the sea as well; hence the number described
in these pages is probably only a small proportion of the total
number of Mastigophora in this region. The Sarcodina, including the
Foraminifera and the Radiolaria, are typically deep-sea forms and
would not be represented by many types in the restricted locality
examined at Woods Hole. Two species, _Gromia lagenoides_ and
_Truncatulina lobatula_, alone represent the great order of
Foraminifera, while the still larger group of Radiolaria is not
represented at all.

The Protozoa described are distributed among the different orders as
follows:*


Class SARCODINA.
   Subclass RHIZOPODA.
      Order AMOEBIDA.
            1. _Amoeba guttula_ Duj
            2. _Amoeba_ sp.
            3. _Trichosphærium sieboldi_ Schn.
      Order RETICULARIIDA.
         Suborder IMPERFORINA.
            4. _Gromia lagenoides_ Gruber.
         Suborder PERFORINA.
            5. _Truncatulina lobatula_ Walker & Jacob.
   Subclass HELIOZOA.
      Order APHROTHORACIDA.
            6. _Actinophrys sol_ Ehr.
      Order CHLAMYDOPHORIDA.
            7. _Heterophrys myriapoda_ Archer.
Class MASTIGOPHORA.
   Subclass FLAGELLIDIA.
      Order MONADIDA.
            8. _Mastigamoeba simplex_, n. sp.
            9. _Codonoeca gracilis_, n. sp.
           10. _Monas_ sp.
      Order CHOANOFLAGELLIDA.
           11. _Monosiga ovata_ S. Kent.
           12. _Monosiga fusiformis_ S. Kent.
           13. _Codonosiga botrytis_ (Ehr.) J. Cl.
      Order HETEROMASTIGIDA.
           14. _Bodo globosus_ Stein.
           15. _Bodo caudatus_ (Duj.) Stein.
           16. _Oxyrrhis marina_ Duj.
      Order EUGLENIDA.
           17. _Astasia contorta_ Duj.
           18. _Anisonema vitrea_ Duj.
      Order SILICOFLAGELLIDA.
           19. _Distephanus speculum_ Stöhr.
   Subclass DINOFLAGELLIDIA.
      Order ADINIDA.
           20. _Exuviælla lima_ Clenk.
           21. _Exuviælla marina_ Clenk.
      Order DINIFERIDA.
           22. _Gymnodinium gracile_ Bergh.
           23. _Glenodinium cinctum_ Ehr.
           24. _Glenodinium compressa_, n. sp.
           25. _Peridinium digitale_ Pouchet.
           26. _Peridinium divergens_ Ehr.
           27. _Ceratium tripos_ Nitsch.
           28. _Ceratium fusus_ Ehr.
           29. _Amphidinium operculatum_ Clap. & Lach.
Class INFUSORIA.
   Subclass CILIATA.
      Order HOLOTRICHIDA.
         Family ENCHELINIDÆ.
           30. _Lacrymaria lagenula_ Cl. & Lach.
           31. _Lacrymaria coronata_ Cl. & Lach.
           32. _Trachelocerca phoenicopterus_ Cohn.
           33. _Tiarina fusus_ Cl. & Lach.
           34. _Mesodinium cinctum_, n. sp.
         Family TRACHYLINIDÆ.
           35. _Lionotus fasciola_ Ehr.
           36. _Loxophyllum setigerum_ Quenn.
         Family CHLAMYDODONTIDÆ.
           37. _Nassula microstoma_ Cohn.
           38. _Chilodon cucullulus_ Müll.
           39. _Dysteria lanceolata_ Cl. & Lach.
         Family CHILIFERIDÆ.
           40. _Frontonia leucas_ Ehr.
           41. _Colpidium colpoda_ Ehr.
           42. _Uronema marina_ Duj.
         Family PLEURONEMIDÆ.
           43. _Pleuronema chrysalis_ Ehr.
           44. _Pleuronema setigera_, n. sp.
           45. _Lembus infusionum_, n. sp.
           46. _Lembus pusillus_ Quenn.
         Family OPALINIDÆ.
           47. _Anoplophrya branchiarum_ Stein.
      Order HETEROTRICHIDA.
         Family BURSARIDÆ.
           48. _Condylostoma patens_ Müll.
         Family HALTERIDÆ.
           49. _Strombidium caudatum_ From.
         Family TINTINNIDÆ.
           50. _Tintinnopsis beroidea_ Stein.
           51. _Tintinnopsis davidoffi_ Daday.
      Order HYPOTRICHIDA.
         Family PERITROMIDÆ.
           52. _Peritromus emmæ_ Stein.
         Family OXYTRICHIDÆ.
           53. _Epiclintes radiosa_ Quenn.
           54. _Amphisia kessleri_ Wrzes.
         Family EUPLOTIDÆ.
           55. _Euplotes charon_ Ehr.
           56. _Euplotes harpa_ Stein.
           57. _Diophrys appendiculatus_ Stein.
           58. _Uronychia setigera_, n. sp.
           59. _Aspidisca hexeris_ Quenn.
           60. _Aspidisca polystyla_ Stein.
      Order PERITRICHIDA.
         Family LICHNOPHORIDÆ.
           61. _Lichnophora macfarlandi_ Stevens.
         Family VORTICELLIDÆ.
           62. _Vorticella marina_ Greeff.
           63. _Vorticella patellina_ Müller.
           64. _Zoothamnium elegans_ D'Udek.
           65. _Cothurnia crystallina_ Ehr.
           66. _Cothurnia nodosa_ Cl. & Lach.
           67. _Cothurnia imberbis_ Ehr.
   Subclass SUCTORIA.
         Family PODOPHRYIDÆ.
           68. _Podophrya gracilis_, n. sp.
           69. _Ephelota coronata_ Wright.
         Family ACINETIDÆ.
           70. _Acineta divisa_ Fraip.
           71. _Acineta tuberosa_ Ehr.
         Family DENDROSOMIDÆ.
           72. _Trichophrya salparum_ Entz.

* This classification includes only the orders and families
  represented at Woods Hole



Genus AMOEBA Auct.

The pseudopodia are lobose, sometimes absent, the body then
progressing by a flowing movement; the body consists of ectoplasm and
endoplasm, the latter being granular and internal, the former hyaline
and external. There is always one nucleus and one vacuole, but both
may be more numerous. Reproduction takes place by division or by
spore-formation. Fresh-water and marine.


Amoeba guttala Duj.  Fig. 1.

A minute form without pseudopodial processes, extremely hyaline in
appearance, and characterized by rapid flowing in one direction.
The body is club-shape and moves with the swollen end in advance.
A comparatively small number of large granules are found in the
swollen portion, while the smaller posterior end is quite hyaline.
Contractile vacuole absent, and a nucleus was not seen.  Frequent in
decomposing vegetable matter. Length 37µ. Traverses a distance of
160µ in one minute.

The fresh-water form of _A. guttula_ has a vacuole, otherwise
Dujardin's description agrees perfectly with the Woods Hole forms.


[Illustration: Fig. 1.--_Amoeba guttala_.]


Amoeba?  Fig. 2.

A more sluggish form than the preceding, distinguished by its larger
size, its dense granulation, and by short, rounded pseudopodia,
which, as in _Amoeba proteus_, may come from any part of the body.
A delicate layer of ectoplasm surrounds the granular endoplasm, and
pseudopodia formation is eruptive, beginning with the accumulation
of ectoplasm. Movement rapid, usually in one direction, but may be
backwards or sideways, etc. Contractile vacuole absent; the nucleus
is spherical and contains many large chromatin granules. Length 80µ;
diameter 56µ.


[Illustration: Fig. 2.--_Amoeba_ sp.]


Genus TRICHOSPHÆRIUM Schneider '78

Synonym: _Pachymyxa hystrix_ Gruber.

Marine rhizopods, globular or irregular in form, and slow to change
shape. Dimorphic. Both forms multinucleate during vegetative life.
Pseudopodia are long, thin, and thread-form, with rounded ends.
Their function is neither food-getting nor locomotion, but probably
tasting. The plasm of both forms is inclosed in a soft gelatinous
membrane. In one form the jelly is impregnated with needles of
magnesium carbonate (Schaudinn), but these are absent in the other
form. The membrane is perforated by clearly defined and permanent
holes for the exit of the pseudopodia. Reproduction occurs by
division, by budding or by fragmentation, but the parts are
invariably multinucleate. At the end of vegetative life the
needle-bearing form fragments into numerous mononucleate parts; these
develop into adults similar to the parent, but without the spines.
At the end of its vegetative life this new individual fragments into
biflagellated swarm-spores which may conjugate, reproducing the form
with needles. Size up to 2 mm.


Trichosphærium sieboldi Schneider.  Fig. 3.

With the characters of the genus. A form which I have taken to be a
young stage of this interesting rhizopod is described as follows:

A minute, almost quiescent, form which changes its contour very
slowly. The membrane is cap-like and extends over the dome-shaped
body, fitting the latter closely. The  endoplasm is granular and
contains foreign food-bodies. Nucleus single, spherical, and
centrally located. Pseudopodia short and finger-form, emerging from
the edge of the mantle-opening and swaying slowly from side to side
or quiescent. The most characteristic feature is the presence of a
broad, creeping sole, membranous in nature and hyaline in appearance.
This membrane is the only evidence of ectoplasm, and it frequently
shows folds and wrinkles, while its contour slowly changes with
movements of body. The pseudopodia emerge from the body between this
membrane and the shell margin. Contractile vacuole absent. Length
42µ, width 35µ. In decomposing seaweeds, etc.

Only one specimen of this interesting form was seen, and I hesitate
somewhat in placing it on such a meager basis. It is so peculiar,
however, that attention should be called to it in the hope of getting
further light upon its structure and mode of life. Its membranous
disk recalls the genus _Plakopus_; its mononucleate condition, its
membranous disk, and the short, sometimes branched, pseudopodia
make it difficult to identify with any phase in the life-history of
_Trichosphærium_. I shall leave it here provisionally, with the hope
that it may be found more abundantly another time.


[Illustration: Fig. 3.--_Trichosphærium sieboldi_]


Genus GROMIA Dujardin '35.

(Dujardin 1835; M. Schultze '62; F. E. Schultze '74; Leidy '77;
Bütschli '83; Gruber '84.)

The form is ovoid or globular, and the body is covered by a tightly
fitting, plastic, chitin shell, which, in turn, is covered by a fine
layer of protoplasm. The flexibility of the shell makes the form
variable as in the amoeboid types. The thickness of the shell is
quite variable. The pseudopodial opening is single and terminal. The
pseudopodia are very fine, reticulate, granular, and sharply pointed,
and form a loose network outside of the shell opening. Nucleus single
or multiple. Contractile vacuole is usually absent. Fresh and salt
water.


Gromia lagenoides Gruber '84.  Fig. 4.

This species is not uncommon about Woods Hole, where it is found upon
the branches of various types of algæ. The body is pyriform, with the
shell opening at the larger end. The chitinous shell is hyaline and
plastic to a slight extent, so that the body is capable of some
change in shape. The shell is thin and turned inwards at the
mouth-opening, forming a tube (seen in optical section in fig. 4)
through which the protoplasm passes to the outside. The walls of this
tube are thicker than the rest of the shell, and in optical section
the effect is that of two hyaline bars extending into the body
protoplasm. A thin layer of protoplasm surrounds the shell and
fine, branching, pseudopodia are given off in every direction. The
protoplasm becomes massed outside of the mouth-opening and from here
a dense network of pseudopodia forms a trap for diatoms and smaller
Protozoa. The nucleus is spherical and contains one or two large
karyosomes. The protoplasm is densely and evenly granular, without
regional differentiation. I have never observed an external layer of
foreign particles, such as Gruber described in the original species.

Length of shell 245µ; largest diameter 125µ.


[Illustration: Fig. 4.--_Gromia lagenoides_.]


Genus TRUNCATULINA D'Orbigny.

A group of extremely variable foraminifera in which the shell is
rotaline; i. e., involute on the lower side and revolute on the upper
(Brady). The shell is calcareous and coarsely porous in older forms.
The characters are very inconstant, and Brady gives up the attempt to
distinguish the group by precise and constant characters.


Truncatulina lobatula Walker & Jacob.

Synonyms: See Brady '84 for a long list.

"It is impossible to define by any precise characters the
morphological range of the present species. Its variations are
infinite." (Brady, p. 660.)

This very common form, which occurs in all latitudes, was found
frequently among the algæ at Woods Hole. Its characters are so
difficult to define that for the present I shall limit my record to
this brief notice. Size of shell 230µ by 270µ.


Genus ACTINOPHRYS Ehr.


The body is spherical and differentiated into granular endoplasm and
vacuolated ectoplasm, but the zones are not definitely separated.
There is one central nucleus and usually one contractile vacuole. The
pseudopodia have axial filaments that can be traced to the periphery
of the nucleus.  Fresh and salt water.

Actinophrys sol Ehr., variety.  Fig. 5.

Synonyms: See Schaudinn '95.

The diameter is about 50µ; the vacuolated ectoplasm passes gradually
into the granular endoplasm. This is the characterization given _A.
sol_ by Schaudinn, and it applies perfectly to the freshwater forms.
If I am correct, however, in placing an _Actinophrys_-like form
found at Woods Hole in this species, the description will have to
be somewhat modified. In this form (fig. 5) there is no distinction
between ectoplasm and endoplasm, and there is an entire absence of
vacuoles. The nucleus is central, and axial filaments were not seen.
The single specimen that I found looked much like a Suctorian of
the genus _Sphærophrya_, but the absence of a firm cuticle and the
presence of food-taking pseudopodia with granule-streaming makes it a
very questionable Suctorian, and 1 place it here until further study
throws more light upon it.

Diameter of body 40µ; length of pseudopodia 120 to 140µ.


[Illustration: Fig. 5.--_Actinophrys sol_.]



Genus HETEROPHRYS Archer.

The body is globular with but slight differentiation into ectoplasm
and endoplasm; one nucleus in the latter; contractile vacuoles
one or many; pseudopodia on all sides, thin, and with peripheral
granule-streaming; surrounded by a globular, rather thick coat of
jelly, which is hyaline inside and granular on the periphery. Fresh
and salt water.


Heterophrys myriapoda Archer.  Fig. 6.

Synonym: _H. marina_ Hert. & Less. '74.

Diameter 25 to 80µ; pseudopodia twice as long as the body diameter;
the plasm often contains chlorophyll bodies (Zoochlorella). The
granular part of the gelatinous layer is thick (up to 10µ). The
spine-like processes are very thin and short. (Schaudinn '95.) The
marine form found at Woods Hole probably belongs to this species,
as described by Schaudinn. The short pseudopodia which give to
the periphery a fringed appearance are quite regularly placed in
connection with the pseudopodia. The latter are not so long as twice
the body diameter, the longest being not more than equal to the
diameter of the sphere. The body inside of the gelatinous covering
is thickly coated with bright yellow cells similar to those
on Radiolaria. The animal moves slowly along with a rolling
motion similar to that described by Pènard '90, in the case of
_Acanthocystis_. Diameter of entire globe 35µ; of the body without
the jelly 18µ. The extremely fine granular pseudopodia are 8 to 35µ
long. Common among algæ.

This form was probably meant by Peck '95, when be figured "a
heliozoön."


[Illustration: Fig. 6.--_Heterophrys myriapoda_.]


KEY TO ORDERS OF FLAGELLIDIA.

Small, body usually amoeboid; 1 or more   Order MONADIDA.
flagella; no mouth

Small; plasmic collar around the          Order CHOANOFLAGELLIDA.
flagellum

With 2 or more flagella; one trails       Order HETEROMASTIGIDA.
behind

With 3 or more flagella, none of which    Order POLYMASTIGIDA.
trails

Large; firm body wall; 1 or 2 flagella;   Order EUGLENIDA.
mouth or pharynx, or both

Medium size; with chlorophyll,            Order PHYTOFLAGELLIDA.
no mouth, usually colonial

Small; silicious skeleton; parasitic      Order SILICOFLAGELLIDA.
on Radiolaria or free                     (One genus,
                                          _Distephanus_ Stöhr)


KEY TO THE FAMILIES OF MONADIDA.

No mouth; 1 or 2 flagella: amoeboid       Family _Rhizomastigidæ_
with lobose or ray-like pseudopodia

Mouth at base of single flagellum;        Family _Cercomonadidæ_
plastic; no pseudopodia

One flagellum; inclosed in gelatinous     Family _Codonoecidæ_
or membranous cups

One flagellum; tentacle like process      Family _Bikoecidæ_
at base of flagellum; inclosed in cup

One main flagellum and 1 or 2             Family _Heteromonadidæ_
accessory flagella


KEY TO MARINE GENERA OF MONADIDA.*

Family _Rhizomastigidæ_:

   1. Flagellum repeatedly thrown off     Genus *_Mastigamoeba_
      and reassumed                       in part

   2. Flagellum never thrown off          3

   3. a. Pseudopodia lobose               Genus _Mastigamoeba_

      b. Pseudopodia ray-like             Genus _Mastigophrys_

Family _Codonoecidæ_:

   1. Goblet-shaped cups adherent         Genus *_Codonoeca_
      by stalk

Family _Heteromonadidæ_:

   1. The long flagellum vibratory        Genus *_Monas_

   2. The long flagellum rigid;           Genus _Sterromonas_
      shorter one vibrates

   * Presence at Woods Hole indicated by asterisk.


KEY TO MARINE QENERA OF CHOANOFLAGELLIDA.

   1. Without gelatinous                  3
      or membranous test

   2. With gelatinous                     4
   or membranous test

   3. a. Attached forms:

         1. Without a stalk, or with      Genus *_Monosiga_
            a very short one

         2. With a long, simple, stalk    Genus *_Codonosiga_

         3. With a long, branched, stalk  Genus _Codonocladium_

      b. Free-swimming                    Genus _Desmarella_

   4. Colonial, and with a gelatinous     Genus _Proterospongia_
      covering

   * Presence at Woods Hole indicated by asterisk.


KEY TO FAMILIES AND MARINE GENERA OF HETEROMASTIGIDA.

   1. Two flagella nearly equal in size   Family _Bodonidæ_

      One main and 2 accessory flagella   Family _Trimastigidæ_

Family _Bodonidæ_:

   1. Body very plastic,                  Genus *_Bodo_
      almost amoeboid

      Body not plastic; with large        Genus *_Oxyrrhis_
      anterior cavity, holding flagella

Family _Trimastigidæ_:

   1. With an undulatory membrane         Genus _Trimastix_
      between accessory flagella

      Without such membrane; flagella     Genus _Costia_
      contained in a ventral groove
      while at rest

   * Presence at Woods Hole indicated by asterisk.


KEY TO MARINE GENERA OF POLYMASTIGIDA.

   1. Body flattened; ends rounded;       Genus _Trepomonas_
      sides hollowed; often with
      wing-like processes; cross
      section S-shaped

   2. Body pyriform; one large            Genus _Tetramitus_
      asymmetrical groove; 4 flagella

   3. Body spherical; many flagella       Genus _Multicilia_
      equally distributed


KEY TO FAMILIES AND MARINE GENERA OF EUGLENIDA.

   1. With deeply-insunk pharynx;         2
      no mouth

      With pharynx and distinct mouth     Family _Peranemidæ_

   2. Body plastic; usually with          Family _Euglenidæ_
      chromatophores and eye-spot

      Body plastic; no chromatophores;    Family _Astastidæ_
      no eye-spot

Family _Euglenidæ_:

      Body _Euglena_-like, inclosed       Genus _Trachelomonas_
      in shell with round opening for
      exit of flagellum

Family _Astastidæ_:

      Body with one flagellum             Genus *_Astasia_

Family _Peranemidæ_:

   1. Body striped; plastic;              Genus _Heteronema_
      two diverse flagella

   2. Body striped; not plastic;          Genus *_Anisonema_
      posterior flagellum longer
      than the other

   3. Body striped; not plastic;          Genus _Entosiphon_
      with rod-like organ in pharynx

   * Presence at Woods Hole indicated by asterisk.


Genus MASTIGAMOEBA F. E. Schultze '75.

(Kent '81; Bütschli '86; Klebs '92; Senn 1900.)

In general the form is oval and either regular in outline or
irregular through the presence of many pseudopodia. One flagellum
usually quite large and distinct. Differentiation of ectoplasm and
endoplasm distinct or wanting. One to several contractile vacuoles.
The pseudopodia are occasionally withdrawn, and the flagellum is the
sole means of locomotion. In some cases the flagellum turns into a
pseudopodium, and, conversely, the pseudopodium at one end may become
a flagellum (see below). In some rare cases the ectoplasm secretes a
gelatinous mantle. Reproduction not observed.

Fresh and salt water.


Mastigamoeba simplex, n. sp.  Fig. 7.

A very small form, first seen in the flagellated stage, aroused my
interest by reason of the fact that its flagellum lost its regular
outline and became amoeboid, turning to a pseudopodium, while at the
same time other pseudopodia were protruded from different parts of
the periphery. In this condition ectoplasm and endoplasm could be
made out with the clearest definition. After the pseudopodia were
well formed, the body became flat and closely attached to the glass
slide. In a short time one of the pseudopodia became longer than the
rest; the body became more swollen; the pseudopodia were gradually
drawn in, with the exception of the more elongate one; this became
active in movement and finer in diameter, until ultimately it formed
a single flagellum at the anterior of a small monadiform flagellate.
The process was repeated two or three times under my observation,
so that I am convinced that it was not a developmental form of
some rhizopod. Several of them were seen at different times during
the summer, and they were always of the same size and form in
the flagellated or amoeboid condition. I did not make out their
reproduction, and I shall not be satisfied that this is a good
species until their life history is known.

In decaying algæ. Length 10µ.


[Illustration: Fig. 7.--_Mastigamoeba simplex_.]


Genus CODONOECA James Clark '66.

(Kent '81.)

Small forms inclosed in cup or "house" of ovoid or goblet shape,
colorless and probably gelatinous (chitin?) in texture, and borne
upon a stalk. The monad does not completely fill the test.
Contractile vacuole single, posterior.


Codonoeca gracilis, n. sp.  Fig. 8.

The cup is urn-shaped with a well-defined neck or collar borne upon a
shoulder-like end of the body. It is hyaline, colorless, and carried
upon a stalk equal in length to the cup or shorter than this. The
animal does not fill the cup, nor is it attached by a filament to
the latter. There is a single flagellum. The nucleus is minute and
lateral in position; the contractile vacuole is in the posterior end
of the body. Total length of cup and stalk 21µ; of cup alone 12µ.
This minute form looked so much like a choanoflagellate that I
supposed it to be one until I discovered an empty case (Fig. 8).


[Illustration: Fig. 8.--_Codonoecea gracilis_.]



Genus MONAS (Ehr.) Stein '78

(Kent '81; Bütschli '86; Klebs '97; Senn 1900.)

The body is small, globular or oval and either free-swimming or
fastened by one of the two flagella. The body is sometimes a little
amoeboid, with short pseudopodial processes. In addition to the main
flagellum, there are usually one or two small flagella at the basis
of the larger one.  The nucleus is usually anterior, and one or two
contractile vacuoles are present.


Monas sp.  Fig. 9.

An extremely small form (3µ) attached by a thread of
protoplasm--perhaps a flagellum, to algæ. The body is ovoid and
the main flagellum is about four times the length of the body. The
contractile vacuole is posterior. Only one specimen was seen and
upon this I shall not attempt to name the species.


[Illustration: Fig. 9.--_Monas_ sp.]


Genus MONOSIGA Kent '81.

(Bütschli '86; Francé '97; Senn 1900.)

Small colorless forms of Choanoflagellida, always naked and solitary.
The posterior end is attached directly to the substratum, or
there is a short stalk not exceeding the body in length. Kent '81
distinguished nine species, but Bütschli questioned the accuracy
of many of these, and in this he was followed by Francé '97, who
recognized three species--_Monosiga ovata_, _M. fusiformis_, and _M.
augustata_. Fresh and salt water.


Monosiga ovata S. Kent '81.  Fig. 10.

Synonyms: _M. brevipes_ S. K.; _M. consociata_ S. K.; _M. limnobia_
Stokes.

The individuals are unstalked or provided with a very short stalk
less than the body in length. The form is spherical or ovate,
broadest at the base and tapering to the extremity. The collar is
somewhat variable in size. In the Woods Hole forms it was about
the length of the body. Oil particles present. Contractile vacuole
posterior, nucleus anterior.

Fresh and salt water. Length of body without the collar 5µ.


[Illustration: Fig.10.--_Monosiga ovata_.]


Monosiga fusiformis S. K.  Fig. 11.

Synonyms: _M. steinii_ S. K.; _M. longicollis_ S. K.

The individuals are unstalked, minute, and of a general flask-shape.
The body is swollen centrally and tapers slightly at each end. There
is no stalk, the body being fixed by the attenuate posterior end.
There are two contractile vacuoles and one nucleus, which is situated
a little above the body center. Fresh and salt water. Length without
collar 9µ; length of collar 3µ.


[Illustration: Fig. 11.--_M. fusiformis_.]


Genus CODONOSIGA (Jas. Clark '67).

(Bütschli '78; Kent '81; Francé '97; Senn 1900.)

This genus, as modified by Francé, is distinguished from the
preceding by the possession of an unbranched stalk much longer than
the body length. The body is naked and of various shapes, and the
individuals are solitary or colonial upon a single stalk. Kent '81
enumerates no less than 10 species, which were cut down by Bütschli
to 1. Francé admits 4--_C. botrytis_ Jas. Clark; _C. grossularia_;
_C. pyriformis_, and _C. furcata_, all S. Kent--but regards the
second and third as merely form varieties of the first.


Codonosiga botrytis (Ehr. sp.) Jas. Clark '67.  Fig. 12.

Francé gives the following synonyms: _Epistylia botrytis_ Ehr.;
_E. digitalis_ Stein, _Zoothamnium parasitica_ Stein; _Anthophysa
solitaria_ Fresenius; _Codonosiga pulcherrima_ Jas. Clark; _Monosiga
gracilis_ S. Kent; _M. globulosa_ S. Kent; _Codonosiga pyriformis_
Kent; _C. grossularia_ Kent; (Francé).

The individuals are small and provided with a long unbranched, or
terminal, simply split stalk. The individuals are single or colonial.
The Woods Hole form measured 22µ over all; the body was 5µ, the
collar 3µ, and the stalk 14µ. No colonies were seen, and only a few
individuals upon red algæ.


[Illustration: Fig. 12.--_Codonosiga botrytis_.]


Genus BODO (Ehr.) Stein.

(Stein '59, Bütschli '83; Klebs '92; Senn 1900.)

The body is naked, usually amoeboid in its changes, and provided with
two flagella, one of which is usually trailed along under and behind
the animal. The anterior end is usually pointed, with the flagella
arising from a minute depression; the posterior end is rounded.
Specific characters very difficult to analyze. Fresh and salt water.


Bodo globosus Stein.  Fig. 13.

The body during movement is globular or ovoid, without any anterior
process. The trailing flagellum is invariably much longer than the
vibratory one. The contractile vacuole lies in the anterior half of
the body. Solid food particles are taken in near base of flagella.

Length of body 9 to 12µ; diameter 8 to 11µ. Common.


[Illustration: Fig. 13.--_Bodo globosus_.]


Bodo caudatus (Duj.) Stein.  Fig. 14.

Synonyms: _Amphimonas caudatus_ Duj.; _Diptomastix caudata_ Kent.

The body is variable in shape, but usually flattened and pointed
posteriorly. An anterior process is almost always present, and
below this the flagella are inserted in a minute depression. The
contractile vacuole is close to the base of the flagella. The
flagella are about the same size, the anterior one usually somewhat
longer. Common. Length 12 to 18µ.

This species was seen by Peck '95 and described as a small
flagellate.


[Illustration: Fig. 14.--_Bodo caudatus_.]


Genus OXYRRHIS Duj.

(Kent '81; Bütschli '86; Klebs '92; Senn 1900.)

Medium-sized forms, somewhat oval in shape, with a rounded posterior
end. The anterior end is continued dorsally in a somewhat attenuate
pointed process. At the base of this process is a large cavity or
funnel, on the dorsal wall of which, or on a projection from this
wall, are two equal-size flagella. When at rest, the flagella are
directed backwards. The nucleus is central. In moving, the posterior
end is invariably in advance. This genus is exceptional among
Mastigophora in that division is transverse instead of longitudinal.


Oxyrrhis marina Duj.  Fig. 15.

With the characters of the genus. Contractile vacuole not seen.
Length 28 to 40µ.


[Illustration: Fig. 15.--_Oxyrrhis marina_.]


Genus ASTASIA Ehr.

Flagellates with one flagellum, a spindle-form body and a high
degree of plasticity, the contour constantly changing. A distinct,
usually striped cuticle is invariably present. "Eye-spots" are
absent. Fresh and salt water.


Astasia contorta Duj.  Fig. 16.

_Astasia inflata_ Duj. '41.

The body is colorless, transparent, and flexible. It is largest in
the center, thence tapering at the two extremities. The surface of
the cuticle is obliquely striated, giving to the animal a distinctly
twisted appearance. The contractile vacuole is in the anterior
neck-like portion of the body. The flagellum is inserted in a
distinct oesophageal tube, into which the contractile vacuole
empties. This tube is continued into a deeper pharyngeal apparatus of
unknown function.

Common in decaying algæ. Length 60µ; greatest diameter 30µ.


[Illustration: Fig. 16.--Two aspects of _Astasia contorta_.]


Genus ANISONEMA Bütschli

Flagellates with two flagella, of which one is directed forwards and
is concerned with the locomotion of the animal, while the other is
directed backwards and drags after the animal when in motion. Body
slightly compressed dorso-ventrally (fig. 17, section). An oral
furrow is present on the ventral side and the two flagella originate
in it (fig. 17, at left). The vacuole is on the left side. Food
vacuoles are present in the posterior part. The nucleus is central.
Movement creeping.

Fresh and salt water.


Anisonema vitrea (Duj.)  Fig. 17.

Synonyms: _Tropidoscyphus octocostatus_ Stein '83; _Sphenomonas_ Kent
'81; _Ploeotia vitrea_ Senn 1900.

With the characteristics of the genus. It differs from freshwater
forms in having eight furrowed surfaces running somewhat spirally
from the posterior to the oral end. Length 50µ; width 23µ.  This
attractive flagellate was quite common in decaying algæ at Woods
Hole; its shaking movement, its peculiar furrowed surfaces, and,
above all, its perfectly transparent, vitreous appearance, were well
described by Dujardin. Stein's _Tropidoscyphus octocostatus_ is a
fresh-water form which may possibly be a distinct species, especially
as it is described with both flagella directed forwards.


[Illustration: Fig. 17.--_Anisonema vitrea_.]


Genus DISTEPHANUS  Stöhr.

An aberrant flagellate bearing a single flagellum and a silicious
skeleton resembling those of the Radiolaria. The skeleton consists
of two rings of different diameter parallel with one another and
connected by silicious bars. From the wider ring half a dozen bars
radiate outwards and a similar number of short thorn-like bars point
inwards obliquely. The color is yellow, and except for the flagellum
the form might easily be mistaken for a Radiolarian, as has been the
case repeatedly.


Distephanus speculum Stöhr.

_Dictyocha speculum_ Stöhr; _Dictyocha_ Auc.

With the characters of the genus.

A single specimen only of this very interesting form was seen at
Woods Hole. It occurred in a collection of tow made near the end of
the wharf during the evening.


KEY TO FAMILIES OF DINOFLAGELLIDIA.

   1. No crossfurrow; two free flagella   Family _Prorocentridæ_

   2. One or more cross-furrows           3

   3. Cross-furrow nearly central         Family _Peridinidæ_
      (cf. _Oxytoxum_)

      Cross-furrow close to               Family _Dinophysidæ_
      anterior end

      Several cross-furrows               Family _Polydinidæ_
      and flagella                        (One genus, _Polykrikos_.)


KEY TO MARINE GENERA OF PROROCENTRIDÆ.

Diagnostic characters: The transverse furrow is absent and the two
flagella arise from the anterior end of the body. The shell may be
bivalved.

   1. No tooth-like process dorsal        Genus *_Exuviælla_
      to the flagellum

   2. With tooth-like process dorsal      Genus _Prorocentrum_
      to the flagellum

   * Presence at Woods Hole indicated by asterisk.


KEY TO MARINE GENERA OF PERIDINIDÆ.

Diagnostic characters: The cross-furrow is nearly central (see,
however, _Oxytoxum_); the body may or may not have a shell; the
shell may or may not be composed of distinct plates; the plates are
distinguished as _equatorial_ (_i.e._, bordering the cross-furrow),
_apical_, and _antapical_, while still another, the "rhombic plate",
may be present, extending from the cross-furrow to the apex.

   1. Without distinct shell              Genus *_Gymnodinium_

      With a distinct shell               2

   2. Shell not composed of definite      3
      plates

      Shell composed of definite plates   4

   3. Cross-furrow replaced by            Genus _Ptychodiscus_
      thin-skinned band

      Cross-furrow well defined;          Genus _Protoceratium_
      reticulate markings raised
      on shell-surface

      Cross-furrow well defined;          Genus *_Glenodinium_
      no markings

   4. Two parts of shell equal or         5
      nearly equal

      Two parts of shell very unequal     11

   5. With transverse flagellum in        6
      a distinct furrow

      Transverse flagellum not in a       10
      furrow

   6. With horns, or with wing-like       7
      processes

      Without processes of any kind       9

   7. Processes small, wing-like,         Genus _Diplopsalis_
      around flagellum-fissure

      Processes horn-like                 8

   8. Anterior part with 7 equatorial     Genus *_Peridinium_
      and 1 rhombic plates

      Anterior part with 5 equatorial     Genus _Gonyaulax_
      and no rhombic plates

      Anterior part with 3 equatorial     Genus *_Ceratium_
      and no rhombic plates

   9. Anterior part with 14 equatorial    Genus _Pyrophacus_
      and 1 rhombic plates

      Anterior part with 7 equatorial     Genus _Goniodoma_
      plates

      Anterior part with 4 equatorial     Genus _Amphidoma_
      plates

  10. Apical extremity drawn out          Genus _Podolampas_
      into a tube

      Apical extremity not drawn out      Genus _Blepharocysta_
      into a tube

  11. Cross-furrow deep, with great       Genus _Ceratocorys_
      ledge-like walls


      Cross-furrow wide, no ledge-like    Genus _Oxytoxum_
      walls

   * Presence at Woods Hole indicated by asterisk.


KEY TO MARINE GENERA OF DINOPHYSIDÆ.

Diagnostic characters: The cross-furrow is above the center of the
body, and its edges, as well as the left edge of the longitudinal
furrow, are usually produced into characteristic ledges; those of
the cross-furrow usually form great funnel-like anterior processes,
while those of the longitudinal furrow usually form great, lateral,
wing-like processes ornamented by ribs and other markings.

   1. Without shell; longitudinal         Genus *_Amphidinium_
      furrow may open & close

   2. With shell; longitudinal furrow     3
      unchangeable

   3. With distinct apical funnel         4

      No apical funnel                    Genus _Phalacroma_

   4. With great wing-like ledge          5

      Ledges very small; body long,       Genus _Amphisolenia_
      needle-like

   5. Ledge of longitudinal furrow        6
      extends to posterior end

      Ledge of longitudinal furrow        Genus _Dinophysis_
      does not extend to posterior end
      (Recorded by Peck ('93-'95) as very abundant at Woods Hole
      and in Buzzards Bay.)

   6. Ledge is continued dorsally to      Genus _Ornithocercus_
      the cross-furrow

      Ledge is not continued dorsally     7

   7. With deep dorsal cavity;            Genus _Citharistes_
      secondary funnel not notched

      No dorsal cavity; secondary         Genus _Histioneis_
      funnel deeply notched

   * Presence at Woods Hole indicated by asterisk.


Genus EXUVIÆLLA Cienkowsky '82.

(Klebs '81; Pouchet '83, '86.)

The form varies from globular to ovoid, with occasionally a sharp
posterior end. Shells are usually somewhat compressed, and consist
of two valves, which frequently slide one over the other in such a
manner as to show the structure with great clearness. The right shell
may have a distinct indentation in the anterior edge. There are two
lateral, discoid, brown chromatophores, each of which possesses a
central amylum granule. The nucleus is posterior. Salt water.


Exuviælla lima Ehr.  Fig. 18.

Synonyms _Pyxidicula_ Ehr.; _Cryptomonas_ Ehr.; _Prorocentrum lima_
Kent; _Amphidinium_ Pouchet.

The shell is ovate, rounded and swollen posteriorly. The anterior
border of both shells is slightly indented. The shell is quite thick.
The animal moves through the water very slowly. Dark brown in color.
Length 48µ; width 44µ.


[Illustration: Fig. 18.--_Exuviælla lima_.]


Exuviaella marina Cienkowsky.  Fig. 19.

A smaller form than the preceding, more elliptical in outline, with
a thinner shell and with large granules throughout the endoplasm.
The nucleus is spherical and subcentral in position and possesses a
distinct central granule. This may be a small variety of _E. lima_.


[Illustration: Fig. 19.--_Exuviælla marina_.]


Genus GYMNODINIUM Stein '78.

(Bergh '81; Kent '81; Pouchet '83, '85; Entz '84; Schütt '95.)

The general structure of these forms is similar to that of
_Glenodinium_; the most striking and positive difference is the
absence of a shell. The animals are, as a rule, spherical, yet they
may be pointed at the two ends or at one of them. They are also
frequently flattened dorso-ventrally. The transverse furrow may
be either circular and straight around the body or may describe a
spiral course, passing even twice around the body. The flagella
arise near cross-furrow or, in some cases, in longitudinal furrow.
Chromatophores may or may not be present and food-taking is holozoic,
in many cases at least. In some cases ectoplasm and endoplasm can be
distinguished. Fresh and salt water.


Gymnodinium gracile Bergh '82, var. sphærica, n.  Fig. 20.

The body is divided by the transverse furrow into a shorter anterior
and a longer posterior part. The longitudinal furrow is broader at
the posterior extremity than at the cross-furrow. The structural
feature upon which this new variety is made is the unvarying
plumpness of the body, making it almost spherical, except for
a slight flattening dorso-ventrally. The nucleus is large and
ellipsoidal, with characteristic longitudinal markings of chromatin.
The endoplasm is evenly granular, with a number of large ingested
food bodies. The color is brown, not rose-red as in Bergh's species,
nor is the Woods Hole form as large as the latter. Length of body
68µ; width 55µ. Common.


[Illustration: Fig. 20.--_Gymnodinium gracile_, var. _sphærica_.]


Genus GLENODINIUM (Ehr.), Stein '83.

(Bergh '82; Bütschli '86; Pouchet '85; Daday '86.)

Small globular forms with two distinct furrows, one transverse around
the body, the other longitudinal upon the face only. The shell is
soft and structureless with a distinct aperture near the meeting
point of the two furrows. The endoplasm usually, but not always,
contains a bright red eye-spot.

Fresh and salt water.


Glenodinium compressa, n. sp.  Fig. 21, a, b, c.

This species resembles _G. acuminata_ of Ehrenberg except that it is
strongly compressed laterally. The longitudinal furrow extends nearly
to the extremity of the animal. It begins as a narrow slit and widens
as it progresses upon the left side; it also becomes much deeper
on this side and at the bottom of the depression the longitudinal
flagellum is inserted. The transverse furrow runs evenly around the
body near the upper pole, giving to the shell almost the aspect of
an _Amphidinium_. Brown chromatophores may or may not be arranged
radially about a central amylum granule. One striking characteristic
is the depth of the two furrows. The nucleus is elongate and somewhat
curved; it lies against the posterior wall of the rather thick shell.
Not uncommon.

Length 40µ; breadth 32µ; width 18µ.

The posterior end of the animal is often somewhat pointed and this
point frequently becomes attached, so that the animal whirls around
upon it as upon a pivot.


[Illustration: Fig. 21 a, b, c.--_Glenodinium compressa_, n. sp.]


Glenodinium cinctum Ehr.  Fig. 22.

The body is globular, smooth, and homogeneous.  Brown chromatophores
arranged radially, each in the form of a cone, the base of which
rests against the shell while the points turn inward.  A bright-red
eye-spot may or may not be present; when present it is placed near
the junction of the two furrows. The longitudinal furrow is small.
Fresh water and salt.

Length and diameter the same, 21µ.

This species was observed by Peck '93.


[Illustration: Fig. 22.--_Glenodinium cinctum_.]


Genus PERIDINIUM Ehr. '32, Stein '83.

(Claparède & Lachmann '58; Bergh '81; Pouchet '83; '85; Gourret '88;
Bütschli '86.)

The form is globular, ovoid or elongate, the apex frequently drawn
out into a long tube. The transverse and longitudinal furrows are
quite distinct, the former having often a spiral course about the
body. The two halves of the body are similar, the posterior being
somewhat shorter; the anterior half has seven equatorial plates, an
oral plate, two lateral apical plates, and one or two dorsal plates.
The two antapical plates frequently have a tooth-like process. The
bodies are colorless, green or brown.

Fresh and salt water.


Peridinium digitale Pouchet.  Fig. 23.

Synonyms: _Protoperidinium digitale_ Pouchet; _Protoperidinium_ Bergh
p. p.; _P. divergens_ Peck.

The shell is covered with pits of large size. The posterior part
is hemispherical and surmounted by a single horn or spine. The
transverse furrow is very oblique, and its two extremities are united
by a sigmoid longitudinal furrow. The anterior half bears two spines
or horns of different size, and variable.  The nucleus is spherical
or ellipsoidal and placed in the posterior half of the shell.

Length 68µ; diameter 54µ. Common.

Although the description of Pouchet's _P. digitale_ differs in some
respects from a careful description of the Woods Hole form, I think
the species are the same. The chief difference is in the single horn
of the posterior half; in Pouchet's form this is furrowed by a narrow
groove which runs to the S-shaped longitudinal furrow. In the Woods
Hole form I was unable to make out such a furrow. The flagella, also,
were not seen. This same form was pictured by Peck '95 as _P.
divergens_.


[Illustration: Fig. 23.--_Peridinium digitale_.]


Peridinium divergens Ehr.  Fig. 24.

Synonym: _Ceratium divergens_ Kent.

The shell is spheroidal, widest centrally, attenuate and pointed
posteriorly; the anterior portion is armed with two short, pointed
horns, each of them having a toothed process at the basal portion
of the inner margin. They are frequently colorless and beautifully
transparent, the body being free from large opaque granules; again
they are colored brown or yellow. The nucleus is large and elongate
and finely granular. 75µ long and 68µ in diameter. Common.


[Illustration: Fig. 24.--Ventral and dorsal aspects of _Peridinium
divergens_.]


Genus CERATIUM (Schrank).

(Stein '78; Perty '52; Clap & Lach. '58; Bergh '82; Pouchet '83;
Gourret & Roeser '88; Bütschli '85; Kent '81; Senn 1900; Schütt '98.)

The general shape is a flattened sphere with three long processes
or horns. The cross-furrow is either spiral or circular; the
longitudinal furrow is usually wide and occupies the greater part of
the anterior half of the shell. The shell is thick, reticulate or
striped, and sometimes provided with short spines; often distinctly
porous. The anterior half is composed of 3 equatorial and 3 apical
plates, the latter being continued into the horn-like process. The
posterior half is composed of 3 equatorial and one apical plate
continued into the posterior horn. The right posterior plate is
continued into a similar horn which may remain rudimentary or be
continued into a considerable process. Similarly the left posterior
horn is usually developed, but remains small. There may be from 2 to
3, 4, and 5 horns. Chromatophores usually present, green to yellow
brown.

Fresh and salt water.


Ceratium tripos Ehr.  Fig. 25.

The body is somewhat triangular and bears three horns, two of which
are shorter than the other one and slightly curved upward.

Length, including the horns, 290µ.


[Illustration: Fig. 25.--_Ceratium tripos_.]


Ceratium fusus Ehr.  Fig. 26.

Synonym: _Peridinium fusus_ Ehr.

The animal is very elongate, due to the presence of two long horns
at the extremities of the body. Color, yellow with chromatophores.
Length 285µ; width 23µ.

Both of these species are common in the tow and in the algæ at the
edge of the wharf. Both of them are mentioned by Peck in '93 and '95.


[Illustration: Fig. 26.--_Ceratium fusus_.]


Genus AMPHIDINIUM Clap. & Lach.

The body is ovoid to globular and usually much flattened
dorso-ventrally. The anterior portion is very much reduced and is
somewhat head-like or cap-like. The longitudinal furrow extends
through the entire posterior body length and is apparently capable
of widening and narrowing. It is probably naked (see here Klebs,
Pouchet, Bütschli), although Stein maintained that there is a
delicate cuticle-like shell. Chromatophores of brown or green colors
present and usually grouped radially about a central amylum granule.
The nucleus is posterior.

Fresh and salt water.


Amphidinium operculatum Clap. & Lach.  Fig. 27.

The body is oval and flattened. The transverse furrow is at the
extremity (posterior) of the body and the small portion, which is
thus apparently cut off, is the cap-like or operculum-like structure
which gives the name to the species. Klebs maintains that the two
furrows are not connected, but in this he is certainly mistaken,
provided we have the same species under consideration.  Very common
about Woods Hole.

Length from 40 to 50µ; width 30µ; thickness 15µ.


[Illustration: Fig. 27.--_Amphidinium operculatum_.]



KEY TO INFUSORIA.

1. With cilia                             Subclass _Ciliata_. 3

2. Without cilia (in adult state)         Subclass _Suctoria_
   tentacles

3. a. Without a specialized fringe of     Order _Holotrichida_
      large cilia (ad. zone)

   b. With general covering of cilia      Order _Heterotrichida_
      + adoral zone

   c. With cilia on ventral side          Order _Hypotrichida_
      + adoral zone

   d. With cilia in region of adoral      Order _Peritrichida_
      zone, and about mouth only


KEY TO FAMILIES OF THE HOLOTRICHIDA.

A. Mouth closed except during food        1
   ingestion; no undulating membrane

   Mouth always open; with undulating     2
   membrane

   1. _Gymnostomina_.

      a. Mouth terminal or subterminal.   Family _Enchelinidæ_
         Food is swallowed and not
         introduced by currents

      b. Mouth terminal or subterminal;   Family _Trachelinidæ_
         body frequently drawn out into
         long process; mouth may have
         specialized framework.

      c. Mouth central or posterior;      Family _Chlamydodontidæ_
         pharynx with supporting
         framework

   2. _Trichostomina_.

      a. Mouth anterior or central;       Family _Chiliferidæ_
         pharynx short or absent;
         peristomial depression faint
         or absent

      b. Mouth central; pharynx long,     Family _Urocentridæ_
         tubular; cilia in two broad
         zones

      c. Mouth posterior; form            Family _Microthoracidæ_
         asymmetrical; cilia dispersed
         or limited to oral region

      d. Mouth anterior or central.       _Paramoecidæ_
         Peristomial depression           (One genus, _Paramoecium_)
         clearly marked.

      e. Mouth at end of long peristome   Family _Pleuronemidæ_
         running along ventral side;
         body dorso-ventrally or
         laterally compressed; left edge
         of peristome with great, sail-
         like undulating membrane

      f. Mouth and pharynx distinct,      Family _Isotrichidæ_
         posterior; cilia uniform.
         Parasites in ruminants.

      g. Mouth absent; body vermiform,    Family _Opalinidæ_
         cilia uniform. Usually
         parasites.


KEY TO MARINE GENERA OF ENCHELINIDÆ

Diagnostic characters: Form ellipsoid or ovoid; the mouth is
invariably terminal and is usually round--more rarely slit-formed; it
is closed except when food is taken. An oesophagus when present is a
short, invariably non-ciliated tube which is usually surrounded by
a more or less clearly defined buccal armature. The anus is usually
terminal. Large food particles are swallowed, never introduced by
currents.

   1. Body naked                          3

   2. Body inclosed in a shell or coat    7

   3. a. Cilia uniform about the entire   4
         body; body symmetrical

      b. Cilia in the mouth region        5
         longer than the others; body
         symmetrical

      c. Bristles, or tentacles, in       6
         addition to cilia

   4. Mouth terminal; body ellipsoidal    Genus _Holophrya_
      to ovoid

   5. a. Mouth terminal; body elongate,   Genus _Chænia_
         flexible, and elastic

      b. Mouth terminal; "neck" highly    Genus *_Lacrymaria_
         elastic; entire body
         flexible; conical "head"

      c. Mouth terminal; "neck" highly    Genus *_Trachelocerca_
         elastic; entire body
         flexible; "head" square

      d. Mouth terminal; "neck" highly    Genus _Lagynus_
         elastic; no separate
         mouth-bearing portion

   6. a. Body asymmetrical; bristles      Genus _Stephanopogon_
         in addition to cilia

      b. Body symmetrical; 4 small        Genus *_Mesodinium_
         tentacles from mouth; cilia
         and cirri in girdles

   7. Shell composed of small             Genus *_Tiarina_
      sculptured pieces; cilia long,
      uniform

   * Presence at Woods Hole indicated by asterisk.


Genus LACRYMARIA Ehr. '30.

(Ehrenberg, C. G., 1838; Perty '52; Claparède & Lachmann '58; Stein
59-83; Quennerstedt '66, '67; Fromentel '74; Kent '81; Gruber '84;
Gourret & Roeser '86; Bütschli '88; Schewiakoff '89.)

Body short to very long flask-shape; for the most part contractile,
especially in the neck region. The posterior end is rounded or
pointed. The main character is the mouth-bearing apex, which "sets
like a cork in the neck of the flask." One or more circles of long
cilia at the base of the mouth portion or upon it. The body is
spirally striped. Contractile vacuole terminal, with sometimes one
or two further forward. Macronucleus central, globular to elongate,
sometimes double. Food mainly bacteria. Fresh and salt water.


Lacrymaria lagenula Clap. & Lach.  Fig. 28, a, b.

Synonym: _L. tenuicula_ Fromentel '74.

Body more or less flask-shape, two or three times as long as broad,
with conical apex, which is slightly elastic and protrusible; surface
obliquely striate, with well-defined lines, 14 to 16 in number; cilia
uniform on the body, with a crown of longer ones at the base of the
conical proboscis. The body cilia are not thickly placed except
around the proboscis. The endoplasm is thickly packed with large
granules (food particles) in the anterior half and with finely
granular particles in the posterior half. The elongate macronucleus
lies a little above the center among the larger granules; the
contractile vacuole is double, one on each side of the median line
and at the posterior end of the body among the finer granules. The
anus is posterior. Length 90µ to 160µ; greatest width assumed 65µ.
When fully expanded the posterior end assumes a curious polyhedral
form. (Fig. 28 b.)

This form differs slightly from others of the same species as
described by different observers, the most striking difference being
the presence of two contractile vacuoles in place of the usual one.
These are very slow to fill and grow to a large size before diastole.
The membrane is very tough and retains its form easily under pressure
of the cover glass. Another characteristic feature is the flattening
of the surfaces between the striæ. Decaying algæ.


[Illustration: Fig. 28.--_Lacrymaria lagenula_.]


Lacrymaria coronata Cl. & Lach. '58.  Fig. 29.

Synonyms: _L. lagenula_ Cohn '66; Möbius '88; _L. cohnii_ ? Kent '81;
_L. versatilis_ Quen. '67.

Form flask-like and similar to _L. lagenula_, contractile but tough.
The contractile vacuole is terminal, the proboscis is short, slightly
raised and separated from the body by a deep cleft; the buccal cilia
are inserted part way up on the proboscis. Form changeable, from
short, sac-like to elongate and vermiform. Length 85µ.

This species is not very different from _L. lagenula_, but I noted
that in addition to the elongate nucleus, the body striæ are much
more apparent here and seem to sink into the cuticle, giving the
periphery, especially at the collar region, a curious crenulated
effect. The endoplasm is very densely granular and colored a
blue-green, probably from food particles. The number of striæ is much
larger than in the preceding species. The membrane is very tough and
retains the shape of the body, even with the full pressure of the
cover glass. Micronucleus and trichocysts were not observed.


[Illustration: Fig. 29.--_Lacrymaria coronata_.]


Genus TRACHELOCERCA (Ehr. '83) Cohn '66.

(Quennerstedt '67; Gruber '87; Entz '84; Kent '81; Gourret & Roeser
'88; Bütschli '88; Schewiakoff '89; Shevyakov '96.)

The only well-known representative is very elongate, large (up
to 3 mm. Van Beneden), and very contractile. The main feature of
importance in distinguishing it is the 4-part structure of the mouth
region, which, however, may not be obvious. Pharynx faint and smooth.
Contractile vacuole terminal. Macronucleus in one central body or in
numerous pieces scattered throughout the cell.  Salt water.


Trachelocerca phoenicopterus Cohn '66.  Fig. 30.

Synonyms: _T. sagitta_ Ehr. '40, Stein '59; _T. tenuicollis_
Quennerstedt '67, Kent '81; _T. minor_ Gruber '87, Shevyakov '96.

The body is extremely elongate and ribbon-like, and this, combined
with its wonderful power of extension and retraction, makes it one of
the most curious and interesting of microscopic forms. The anterior
end is square or cylindrical; the type species has a four-sided
mouth, but many specimens may be found which have a plain cylindrical
mouth region. One reason for this may be the fact that the extremity
gets broken off. In one instance I noticed a very large form with the
anterior end under some debris, which evidently held it tight, for
the body of the ciliate was thrashing back and forth and twisting
itself into knots, etc., like a nematode worm. Finally, the anterior
end broke off with about one-tenth of the body; the remainder, in an
hour, had regenerated a new anterior end with long cilia, but with
no indication of four sides. The small anterior piece was also very
lively, moving about and eating like the normal animal; its history,
however; was not followed. This species appears to be variable in
other ways as well; thus, in some cases the posterior end is rounded
(cf. Entz '84); in others it is pointed (cf. Kent '81, Cohn '66, et
al.).

Again, the macronucleus may be a single round body (Entz '84,
Bütschli '88) or in two parts (Kent '81), or in many parts scattered
about the body (Gruber). In the Woods Hole forms the tail is
distinctly pointed and turned back sharply, forming an angle at the
extremity. The cilia on this angular part are distinctly longer than
the rest. The function of this posterior part is apparently to anchor
the animal while it darts here and there upon the tail as a pivot,
contracting and expanding the while. The body is finely striated
with longitudinal markings; when contracted there are no transverse
markings nor annulations. The nucleus is in the form of many
fragments scattered throughout. Length of large specimen 1.7 mm.


[Illustration: Fig. 30.--_Trachelocerca phoenicopterus_.]


Genus MESODINIUM Stein '62.

(Maupas '82, '84; Entz '84; Shevyakov '96.)

The main part of the body is globular or conical, with a short,
platform-like oral region, and a deep annular groove about the
middle of the body. The oesophagus is rather long, and smooth or
longitudinally striped. One or more rings of cirri rise in the
groove. If more than one ring of cirri are present, the anterior set
usually point forward and lie close to the anterior part of the body.
The posterior set, on the other hand, cling close to the posterior
region of the body and give to it a peculiar encapsuled appearance.
The most characteristic feature is the presence of four short
tentacle-like processes which can be protracted and retracted from
the oral region. (Mereschowsky says that the entire anterior half
is more or less contractile.) The macronucleus is horseshoe-shaped
or ovoid and is situated in the posterior half of the body. The
contractile vacuole is also posterior.

Movement consists in rapid swimming, with rotation on its axis, or
in creeping by means of its anterior cirri, or in sudden jumping, by
which it apparently clears a distance of 20 times its diameter in one
bound. Mouth parts may also be used for attachment to foreign bodies.
The moving periods alternate with quiescent periods, during which the
organisms with their outstretched and radiating cirri resemble the
heliozoön _Actinophrys_.


Mesodinium cinctum, n. sp.  Fig. 31.

Body spherical to pyriform, constricted near the middle, the
constriction dividing the body into dissimilar parts. The anterior
part is broadly pyriform, somewhat plastic and hyaline, with an oral
extremity which is sometimes hollow, sometimes evaginated and convex.
Upon this flexible anterior part there are four short but distensible
tentacles. The posterior part is granular and usually filled with
food particles; it is well rounded and holds the nucleus and
contractile vacuole. The entire body is surrounded by a fine cuticle.
The nucleus is elongate and extends through the greater part of the
posterior half. The contractile vacuole lies on one side, near the
girdle. The mouth is on the anterior pole in the tentacle region. The
motile organs are cirri and cilia, all inserted in the constriction.
There are two sets of cirri and one of cilia; the latter stand out
radially from the girdle and are usually in motion. The cirri of
one set, the anterior, extend forward about twice the length of the
anterior half; those of the posterior set closely engirdle the lower
half, reaching not quite to the posterior extremity. These are
somewhat hyaline and are closely approximated, giving the impression
of a tight-fitting crenulate casing about the lower half. The cirri
are sharply pointed, much broader at the base, and the two sets are
so placed that, looked at from above, they have the appearance of a
twisted cord. (Fig. 31 b.) Movement erratic; sometimes the animal
swims steadily forward with mouth in front; again it shoots across
the field of the microscope, either backward or forward or sideways,
through the action of its powerful cirri. It is often quiet, usually
mouth downward, and is held in place by adhesion of the tentacles. In
this position it looks strikingly like a heliozoön.

Length 35µ; greatest width 30µ. Not uncommon.

The chief features by which this species is distinguished from the
frequently described _M. pulex_ of Europe are the number of anterior
cirri and the ring of true cilia in place of the central girdle of
cirri. The European form is described with four anterior bristles;
the present form has from 28 to 32. The radial cilia differ decidedly
from the more powerful cirri and they are not in one plane, so that
counting is difficult; they are not closely set. The presence of
tentacles makes these forms of especial theoretical interest,
especially in the light of the origin of _Suctoria_.


[Illustration: Fig. 31.--Side and top views of _Mesodinium cinctum_.]


Genus TIARINA R. S. Bergh '79.

(Claparède & Lachmann '58.)

Body subcylindrical, pointed posteriorly, two and one-half times
as long as broad; encased in covering composed of separate pieces
arranged in five girdles. The pieces bear processes which rest
against neighboring pieces of the girdle. Mouth large, anus terminal
near contractile vacuole. The macronucleus is simple and round. Salt
water.


Tiarina fusus (Cl. & Lach.) emend R. S. Bergh.

Synonyms: _Coleps fusus_ Cl. & Lach. '58; Daday '86; Möbius '88,
Lauterborn '94; Shevyakov '86.

This form, which resembles _Coleps_ rather closely, was placed as a
separate genus by R. S. Bergh. The skeletal parts consist of five
zones of needles composed of an organized substance and embedded in
the cortical plasm, the last zone coming to a point at the posterior
end. The needles have lateral processes, which give a latticed
appearance to the casing. The cilia are long, with a specialized
crown of still longer ones at the oral end; they arise outside of the
skeletal elements and do not pass between them, as in _Coleps_.


KEY TO MARINE GENERA OF TRACHELINIDÆ.

Diagnostic characters: Body bilateral, or asymmetrical by local
prolongations; usually compressed or flattened laterally, the left
side more convex than the right. The essential feature is the
position and character of the mouth. This is either a long slit
extending from the anterior end well down the ventral surface, or the
posterior part only of a ventral furrow remains open as a round or
elongate mouth some distance from the anterior end. The entire mouth
region of the body is usually drawn out into an elongate tapering
proboscis which is generally curved dorsally at the extremity.
An oesophagus is short or absent altogether; when present it is
supported by a stiff buccal armature. Cilia are uniform about entire
body or limited to the flat right side. Food is swallowed.

1. a. Proboscis easily distinguished      2
      from the main body

   b. Proboscis not marked off from       Genus *_Loxophyllum_
      main body; body flat;
      both surfaces striated

2. a. Mouth runs the entire length        Genus _Amphileptus_
      of proboscis; entire body
      uniformly ciliated

   b. Mouth runs the entire length        Genus *_Lionotus_
      of proboscis; body flat; right
      side only is ciliated

   c. Proboscis much drawn out,           Genus _Dileptus_
      flexible; mouth at its base

   * Presence at Woods Hole indicated by asterisk.


Genus LOXOPHYLLUM Dujardin '41.

(Duj. '41; Wrzesniowski '69; Quennerstedt '65; '67; Cohn '66; Entz
'84; Gourret & Roeser '88; Bütschli '88; Shevyakov '96.)

The body is flat and somewhat leaf-shape, flexible, and elastic. The
anterior end is somewhat proboscis-like and flexible, but is not
sharply demarcated as in _Lionotus_. The central portion of the body
is developed into a more or less arched dorsal mass, which usually
contains the nuclei and contractile vacuoles. As a result of this
local thickening, the body is surrounded by a thin hyaline margin.
This, however, may be absent on the right side in some species. The
mouth reaches from the anterior extremity to a short distance from
the end, and usually approaches the left edge. An anus is present
near the posterior end of the dorsal swelling. Trichocysts are
numerous on the ventral surface, and often on the dorsal surface,
where they are inclosed in minute papilla-like swellings.
Cilia-distribution controverted. Maupas and Bütschli hold that
ventral surface alone is ciliated; others (Kent and Dujardin) that
cilia are uniformly distributed. The entire body, dorsal and ventral
surfaces alike, are uniformly striated. The contractile vacuole lies
posteriorly, on the right side and in the dorsal swelling. In the
fresh-water form _L. meleagris_, it is connected with a long canal
whose swellings are frequently taken for additional contractile
vesicles (Bütschli); in the marine form described below the canal is
not developed and a series of vacuoles takes its place; these are
all contractile. The macronucleus may be single, double, quadruple,
band-formed, or rosette-formed. Movement is steadily progressive and
peculiarly gliding. Fresh and salt water.


Loxophyllum setigerum Quenn. '67.

Synonyms: _Litosolenus armatus_ Stokes '93; _Litosolenus verrucosa_
Stokes '93.

The body is flattened, irregular in outline, obtusely pointed
anteriorly, the point being turned to the right; rounded posteriorly.
The left edge is nearly straight, the right considerably arched with
a few setæ on the posterior half. Contractile vacuoles are numerous,
dorsal in position and on the right side. The macronueleus is beaded,
the several spheres connected.


Variety armatum (Cl. & Lach.) Fig. 32.

Under the name _Litosolenus armatus_, Stokes described a form from
brackish water near New York, which should unquestionably be referred
to the genus _Loxophyllum_, and I believe to Quennerstedt's species
_setigerum_. While the latter possesses only a few setæ, the former
has a number of them, and Stokes described his species as having a
variable number. For this reason I include the Woods Hole form under
the tentative name _armatum_, as a variety of Quennerstedt's _L.
setigerum_. The flat margins are distinctly striated longitudinally,
and faintly marked radially, on the dorsal surface. Longitudinal
elevated striæ also run the length of the dorsal hump and upon the
entire ventral surface. The ventral surface is alone ciliated. Upon
the edges of the flat border are sharp-pointed, colorless, spine-like
processes, situated at equal distances around the entire periphery
except at the anterior end. Each spine is thick at the base and
tapers to a full point which is curved upward--_i. e._, dorsally
(fig. 32, a, b). The entire body is plastic and contractile, turning
its leaf-like edge readily over objects upon which it creeps. The
cilia are fine and uniform, with a tendency to lengthen in the oral
region.

Length 100µ; greatest width assumed on contraction 85µ; when normal
about 50µ.


[Illustration: Fig. 32.--_Loxophyllum setigerum_, var. _armatum_. a,
b, c, ventral, dorsal, and lateral aspects.]


Genus LIONOTUS Wrzesniowski '70.

(Incorrectly called _Litonotus_ by many. Entz '84; Gruber '84;
Bütschli '88; Kent '81; Schewiakoff '89; Shevyakov '96.)

The body is elongate and somewhat lance-shaped, widest at the central
part and tapering to a point at the anterior end. The posterior end
may be similarly tapered or rounded. The anterior end frequently
proboscis-like, flat, and flexible, while the entire body is more or
less elastic and contractile.  The right side is flattened and alone
provided with cilia, while the left side of the body proper is
arched; on the left side of the proboscis is a row of coarse cilia
resembling an adoral zone, and a row of trichocysts. A long peristome
stretches down the thin, ventral side of the proboscis, and the mouth
proper is situated at the junction of the proboscis and body; the
mouth, as a rule, is invisible. The ciliated right side alone is
striated in the majority of species. The contractile vacuole may be
single or multiple, usually in the posterior region of the body and
dorsal in position. The macronucleus is usually double, rarely single
or quadruple, but may occasionally break into numerous smaller
pieces.  Movement, free-swimming or gliding, with especial tendency
to get under clumps of foreign matter.

Fresh and salt water.


Lionotus fasciola Ehr.  Fig. 33.

Synonyms. _Amphileptus fasciola_ Ehr. '38; Dujardin '41; Lachmann
          '56;  Cohn '66, Diesing '65.
          _Loxophyllum fasciola_ Claparède & Lachmann '58;
          Balbiani '61.
          _Loxophyllum duplostriatum_ Maupas '83. Shevyakov '96.

Body frequently brown or brilliant yellow in color, somewhat sigmoid
in form with tapering anterior end, the extremity of which is turned
dorsally. The proboscis is about half the entire length and is not
sharply marked from the rest of the body but tapers gradually, its
base being equal to the diameter of the body at its middle point. The
body is slightly contractile and the posterior end is carried to a
rounded point, but not into a distinct tail. Unlike the fresh-water
variety, this one has no hyaline margin nor hyaline caudal region,
and the contractile vacuole is double or multiple on the dorsal side
near the posterior end. Cilia are present only on the under (right)
side, with, however, a row of large cilia marking the course of the
elongate mouth, upon its left side. The right side is striated, the
left arched and without markings. The endoplasm is finely granular
with, however, larger food particles in the process of digestion,
while specimens are occasionally seen with the natural form
completely lost through distortion caused by over-large captures (Cf.
also Wrzesniowski '70, p. XXIII, fig. 32). Movement continuous, slow,
and gliding; very little tendency to jerking movements. Macronucleus
double, both parts spherical, and placed in about the center of the
larger part of the body; closely approximated but not, as Schewiakoff
described, connected. In conjugation, a large form unites with a
smaller one, the mouth parts being connected. Details of conjugation
and macronuclei not made out. Length 200µ to 600µ.


[Illustration: Fig. 33.--_Lionotus fasciola_.]


KEY TO MARINE GENERA OF CHLAMYDODONTIDÆ.

Diagnostic characters: Form usually ellipsoid, never very elongate.
Transverse section of body circular or elliptical. The mouth is
usually some distance from the anterior end and may be in the
posterior part. Sometimes it is in the center of the ventral
surface, again on the right side. The oesophagus invariably has
a well-developed buccal armature, or a smooth peculiarly built
oesophageal tube. Food particles of large size.

1. Body cylindrical. Cilia about          Genus *_Nassula_
   entire body

   Body flat                              2

2. a. Without a caudal process            3

   b. With a caudal process               5

3. a. Anterior end angular                4
      on left side

   b. Anterior end rounded                Genus _Chlamydodon_

4. a. Dorsal striæ and cilia present,     Genus _Orthodon_
      ventral cilia longer

   b. Dorsal striæ and cilia absent;      Genus *_Chilodon_
      posterior end not pointed

   c. Dorsal striæ and cilia absent;      Genus _Scaphidiodon_
      posterior end pointed

5. a. Caudal spine with posterior         6
      bristle-like cilia

   b. Caudal spine without posterior      Genus _Trochilia_
      bristle-like cilia;
      ventral cilia reduced

6. a. With pigment spot on anterior       Genus _Ægyria_
      angle

   b. Without such pigment spot           Genus _Onychodactylus_

   c. Cilia on right edge only of         Genus *_Dysteria_
      greatly reduced ventral surface

   * Presence at Woods Hole indicated by asterisk.


Genus NASSULA Ehr. '33

(Dujardin '41; Stein '67; Cienkowsky '55; Cohn '66; Clap. et Lach.
'58; Kent '81; Maupas '83; Entz '84; Fabre-Domergue '88; Bütschli
'88; Shevyakov '96.)

The body is ovoid or cylindrical, with well-rounded ends, and in
some cases slightly flattened. The mouth is ventral and placed some
distance from anterior end (1/4 to 1/3 total length). A slight
depression on the ventral surface marks the mouth region, which is
further indicated by larger and more powerful cilia. The rest of the
body is uniformly ciliated. The entire body is marked by clearly
defined spiral stripes. The mouth is circular and the oesophagus is
supported by a considerable armature, which usually extends dorsally
and to the left, rarely to the right. In some cases the structure of
this armature is indistinct; again it can be clearly seen to consist
of definite rods (Stäbchen). The anus is probably always terminal.
Contractile vacuoles are variable in different species. In some cases
there is but one, which is placed at the posterior end or centrally
on the ventral side; in others there may be four--two dorsal and
two ventral. In many cases trichocysts are uniformly distributed.
Sometimes the body is colorless; again, and more often, it is
brightly colored with red, blue, brown, or black pigment. The
macronucleus is globular and central, occasionally band-form and
with numerous attached micronuclei. Food substance varied, usually
vegetable matter, see, however, below. Cysts are globular. Movement
is a steady progression, combined with rolling.


Nassula microstoma Cohn '66.  Fig. 34.

Synonyms: _Paramoecium microstomum_ Cl. et Lach. '58, Gourret et
Roeser '88; _Isotricha microstomum_ Kent '81.

Body subcylindrical, rounded at each extremity, not quite twice as
long as broad. A slight depression on one surface marks the position
of the mouth, this depression being indicated by a row of longer
cilia. The mouth is extremely small and is surrounded by a curious
buccal armature. This is not made up of bars or rods, as in most
species of _Nassula_, but appears perfectly smooth and uniform
except for the considerable swelling at the inner end. The cuticle is
firm and unyielding and marked by longitudinal and somewhat spiral
rows of cilia and trichocysts. Under the microscope this is one of
the most pleasing forms found at Woods Hole. Its color is yellowish
brown from the presence of brilliant particles of coloring matter
held in the cortical plasm, and, as it slowly rolls along, these
particles and the black trichocysts give to the organism a peculiar
sparkling effect. The macronucleus is almost central; the contractile
vacuole posterior. The endoplasm appears well filled with food
bodies, some of which could be distinguished as _Amphidinium_ and
_Glenodinium_.

Length 55µ; greatest diameter 30µ.


[Illustration: Fig. 34.--_Nassula microstoma_.]


Genus CHILODON Ehr.

(Dujardin '41; Engelmann '78; Stein '54, '58; Kent '81; Bütschli '88;
Gruber '83; Cienkowsky '55; Möbius '88; Clap. et Lach '58;
Wrzesniowksi '65; Shevyakov '96.)

Small forms, greatly flattened dorso-ventrally and almost egg-form in
outline. The anterior end is bent distinctly to the left and forms a
characteristic process, which, together with the entire margin of the
body, is soft and flexible. The posterior end is, as a rule, broadly
rounded. The ventral surface is finely striate, and this surface
alone is ciliated. The lines of cilia converge at the mouth, and at
this region the cilia are somewhat larger and more distinct, thus
forming a functional adoral zone. The mouth is median and is situated
in the anterior half of the body. It is surrounded by a well-defined
armature, composed usually of from 10 to 16 rods. The contractile
vacuoles are quite varied and from one to many in number, the
number increasing with the size of the individual. The macronucleus
is usually single, elliptical in form, and centrally placed;
one micronucleus. Reddish granular pigment and trichocysts are
occasionally present.


Chilodon cucullulus Müll., sp.  Fig. 35.

Synonyms; _Colpoda cucullus_ O. F. Müller; _Loxodes cucullulus_;
_Chilodon uncinatus_ Ehr. '58, Perty '52, Dujardin '41; _L. dentatus_
Duj., etc.

This extremely variable form has received so many different names
that it hardly pays to enumerate them. It is one of the commonest
and most widely spread ciliates known, although at Woods Hole I was
surprised to see it so rarely. It is the type species of the genus
and needs no further description. The specimens observed at Woods
Hole had numerous contractile vacuoles and were 42 to 45µ long and
from 28 to 32µ wide.


[Illustration: Fig. 35.--Ventral and dorsal aspects of _Chilodon
cucullulus_.]


Genus DYSTERIA Huxley '57.

(Cl. et Lach. '58; Entz '84; Möbius '88; Shevyakov '96.)

Small forms, firm in outline, and colorless or slightly colored. The
body is somewhat clam-shaped, flattened, slightly curved or straight
on the right side, the other more convex. The true ventral side is
only a narrow strip along the right and anterior edge of the body,
the apparent ventral side being a fold of the very large dorsal
surface which comes around ventrally, forming a valved structure
somewhat analogous to a clam shell. Cilia are limited to the outer
edge of the small ventral surface, which also bears a peculiar spine
at the posterior end. Behind this spine are larger cilia. The mouth
opening lies in the anterior widened portion of the ventral surface
and is connected with a smooth tubular pharynx. The right half of the
dorsal side, _i.e._, the apparent dorsal side, is arched and bears
longitudinal ridges. Two to four contractile vacuoles are placed on
the ventral side. The macronucleus is usually dorsal, elliptical, and
cleft, with one micronucleus attached. Fresh and salt water.


Dysteria lanceolata Cl. et Lach.  Fig. 36.

Synonym: _Cypridium lanceolatum_ Kent '81.

Outline of the flattened body ovoid; body consists of two valve-like
portions; the edge of the right valve is nearly straight, that of the
left valve more or less sinuous; anteriorly it is cut away, obliquely
and posteriorly it has a deep indentation in which the seizing spine
rests. The cilia are confined to the ventral surface, here reaching,
however, from the anterior dorsal extremity to below the posterior
indentation. Posteriorly the cilia become larger, corresponding to
the larger cirri of _D. armata_, which are posterior to the spine.
The mouth lies between the two valves and is surrounded by a long
and smooth buccal armature which passes downward and backward to
the left a distance equal to about half the entire body length. The
macronucleus is situated in the dorsal region in the central part of
the body. There are two contractile vacuoles, one behind the center
of the buccal armature, the other near the inner end of this organ.
Movement is in circles, the animal moving around quite rapidly when
not attached by its posterior process. It is colorless and measures
45µ in length by 27µ in width. Claparède & Lachmann and Shevyakov
describe it as 70µ long.


[Illustration: Fig. 36.--_Dysteria lanceolata_.]


KEY TO MARINE GENERA OF CHILIFERIDÆ.

Diagnostic characters: Mouth never lies behind the middle of the
body; the oesophagus is but slightly developed. The undulating
membranes are placed either on the edge of the mouth or in the
oesophagus. A peristomial depression leading to the mouth is absent
or very slightly indicated.

1. Mouth in the anterior half,            Genus *_Frontonia_
   undulating membrane on left edge
   only; right edge continued in a
   long ventral furrow

2. Two undulating membranes; mouth        Genus *_Colpidium_
   central; no caudal bristles

3. Two undulating membranes; caudal       Genus *_Uronema_
   bristle


Genus FRONTONIA Ehr. (Cl. & Lach. '58?).

(Ehrenberg, subgenus of _Bursaria_ '38; Claparède & Lachmann '58;
Bütschli '88; Shevyakov '96.)

Form elongate and cylindrical, or often flattened dorso-ventrally,
with round or pointed ends. It is usually plastic and contractile.
Cilia are evenly distributed about the body and are similar in
length. The large, open mouth lies on the anterior half of the
ventral surface, and is elongate and oval in outline. On its left
edge is a well-defined membrane which stretches across to the right
side of the mouth. On the right edge is a small, longitudinally
striped tract which is free from trichocysts and smooth in
appearance. This tract is continued posteriorly in a long furrow,
which in some cases reaches the posterior end of the animal. A few
rows of cilia in this furrow vibrate differently from the others and
give the effect of a membrane (Bütschli). The oesophagus is extremely
short and hard to make out. The body is usually covered uniformly
with trichocysts, often of considerable size. There are 1 or 2
vacuoles with long canals radiating throughout the endoplasm. The
macronucleus is oval and centrally placed. Micronuclei vary from
one to many. An anal opening is placed at the end of the long
ventral furrow. The plasm is colorless or green by the presence of
Zoochlorella, or colored brown or black by pigments. In these cases
there is a considerable pigment mass on the anterior end. Movement
is regular, forward, and combined with rotation. Food consists of
foreign objects, diatoms, other protozoa and the like. Fresh and salt
water.


Frontonia leucas Ehr.  Fig. 37.

Synonyms: _Frontonia vernalis_ Ehr. '38; _Bursaria leucas_ Allman
'55, Carter '56; _Panophrys leucas_ Duj. '41, Stein '67; _Panophrys
vernalis_ Dujardin '41, Stein '67; _P. chrysalis_ Duj. '41, Fromentel
'74; _Cyrtostomum leucas_ Stein '67, Kent '81.

Form ovoid, elongate, occasionally a little flattened
dorso-ventrally. Mouth in the anterior third of the body. The left
edge of the mouth carries a distinct undulating membrane; the right
edge is plain, longitudinally striated and bears cilia. It is
slightly depressed and the depression is carried posteriorly in the
form of a shallow furrow which reaches to the posterior end. The
contractile vacuole is on the left side, the spheroidal nucleus on
the right side of the furrow. The body is uniformly covered with fine
cilia, and the periphery is uniformly studded with large trichocysts,
except along the furrow. Food consists of dinoflagellates and other
small forms. Color dark brown to black.

Length 330µ; width 200µ.

This form differs considerably from the fresh-water _Frontonia
leucas_ as described by Schewiakoff '89, especially in the extreme
length of the peristomial furrow, in the position of the nucleus and
contractile vacuole, and in the nature of the water canals. These
in the Woods Hole form are very irregular in size and very much
branched, not uniform as in Lieberkühn's (see Bütschli) figure of
_Frontonia leucas_, nor radiating as in Schewiakoff's description.
This may be the same species as _Frontonia marina_, of Fabre-Domergue
'91, whose description and figure I have not seen.


[Illustration: Fig. 37.--_Frontonia Leucas_.]


Genus COLPIDIUM Stein '60

(Bütschli '88; Maupas '83.)

The general form is oval, slightly compressed laterally with the
dorsal side strongly arched. The ventral side is slightly incurved.
The anterior end is somewhat smaller than the posterior end, which is
broadly rounded. The mouth is placed some distance from the anterior
end in an oral depression and opens into a tubular oesophagus. There
are usually two undulating membranes which do not extend beyond the
mouth borders. The right undulating membrane extends down into the
oesophagus and appears to be attached to the walls of the latter. The
body stripes in front of the mouth are twisted to the left. The anus
is terminal and the contractile vacuole may be terminal or situated
forwards in the dorsal region. The macronucleus is spherical and
has one  micronucleus attached. Food consists mainly of bacteria.
Movement rapid, but interrupted.

Fresh and salt water, common in infusions.


Colpidium colpoda Ehr., sp.  Fig. 38.

Synonyms: _Colpidium cucullus_ Kent '81; _C. striatus_ Stokes '85;
_Kolpoda cucullus_ Duj. '41; _Paramoecium colpoda_ Ehr. '38,
Quennerstedt '67; _Plagyiopyla nasula_ Kent '81, G. & R. '86;
_Glaucoma pyriformis_ G. & R. '86; _Tillina campyla_ Stokes '85, '88.

The body is oval, somewhat larger posteriorly, and a little
compressed dorso-ventrally. The anterior end is twisted a little from
the right to the left (more evident in fresh-water forms), and leans
somewhat toward the ventral side. Under this portion, on the ventral
side, lies the mouth in a large depression just above the middle of
the body. The entire body is covered with uniform and delicate cilia,
which are placed in longitudinal rows. These rows are almost straight
on the dorsal side, but bend on the ventral surface, following
the contour of the twisted anterior portion. The endoplasm is
finely granular; the oesophagus leading into it is very distinct.
Schewiakoff ('89) describes two membranes, an inner and an outer;
Maupas ('83) describes them as right and left. In the present species
I was able to make out only one. The macronucleus is central,
spherical in form, and bears a single minute micronucleus. The
contractile vacuole is posterior and dorsal to the long axis of the
body. The anus is ventral to this axis and also posterior. Length
45µ, width 20µ. Common.

This marine variety is much smaller than the fresh-water form and the
form differs in a number of respects, viz, in the anterior torsion
and in the structure of the mouth. These may be, however, only
individual variations of a widely spread species, and I believe it is
perfectly safe to describe this as _Colpidium colpoda_.


[Illustration: Fig. 38.--_Colpidium colpoda_.]


Genus URONEMA Duj. '41.

(Quennerstedt '69; Cohn '66; Kent '81; Bütschli '81; Schewiakoff '89;
Shevyakov '96.)

Minute forms; colorless and constant in body form. The form is oval,
slightly compressed on the ventral side, while the dorsal side is
distinctly arched. The membrane is distinctly marked by rather widely
separated striæ. These occasionally have a spiral course about the
body; in all cases they can be easily counted. The mouth is large
and placed near the center of the ventral surface. It is sometimes
approached by a very shallow depression or peristome from the
anterior end, and marked by two rows of cilia. An undulating membrane
extends down the mouth. Oesophagus absent. A long, stiff bristle
extends outwards from the posterior end. The contractile vacuole is
terminal or subterminal and near the anal opening. The macronucleus
is spherical, centrally placed, and with one micronucleus closely
applied. Movement is rapid and usual forwards in a straight line,
often found resting, however, with outstretched cilia in contact with
some foreign body. Food mainly bacteria. Fresh and saltwater, usually
in decomposing vegetable substances.


Uronema marina Duj.  Fig. 39.

Synonyms: _Enchelys triquetra_ Dujardin; _E. corrugata_ Duj.;
_Cryptochilum griseolum_ Maupas '83; _Philaster digitiformis_
Fabre-Domergue '85.

Small animals with ellipsoidal form and about twice as long as
broad. The mouth lies in the upper half of the body and bears a
well-developed undulating membrane upon its left edge. The membrane
is longitudinally striped and covered with long and vibratile cilia.
The right edge of the mouth bears cilia which are about the same in
size as the body cilia, but are more closely inserted (Schewiakoff).
The most characteristic feature is the long caudal bristle, which
is extremely delicate and about two-thirds the length of the body.
Schewiakoff thinks this bristle has a sensory function. I could not
make this out, for although other protozoa ran against this bristle,
often bending it well over to one side, the animal showed no sign
of irritability but lay quiescent. A spherical macronucleus with
attached micronucleus lies in the center of the body. The contractile
vacuole is posterior in front of the bristle. The macronucleus was
found to be double, as though just divided, in a large percentage of
cases. This may be a precocious division of the nucleus long before
signs of the body division are evident. Such a phenomenon, however,
is rare, the macronucleus usually dividing at a late stage of cell
division. Length 30 to 50µ; width 15 to 20µ. Common in decomposing
algæ.


[Illustration: FIG. 39.--_Uronema marina_.]


KEY TO MARINE GENERA OF PLEURONEMIDÆ.

Diagnostic characters: The mouth is at the end of a long peristome
running along the ventral side; the body is dorso-ventrally or
laterally compressed. The entire left edge of the peristome is
provided with an undulating membrane which occasionally runs around
the posterior end of the peristome to form a "pocket" leading to
the mouth. The right edge of the peristome is provided with a
less-developed membrane. There may or may not be a well-developed
pharynx.

Body small; not produced into             Genus *_Pleuronema_
 neck-like elongation

Body medium-sized; anterior end           Genus *_Lembus_
produced into neck-like elongation

   * Presence at Woods Hole indicated by asterisk.


Genus PLEURONEMA Dujardin '41.

(Perty '52; Clap. & Lach. '58; Stein '59, vol. I; Quennerstedt '67;
Kent '81; Bütschli '88; Schewiakoff '89; Shevyakov '96.)

Small to medium-sized ciliates, with an unchanging form. They are
somewhat lens-shape and laterally compressed, the two surfaces
about equally arched. The ventral surface is nearly straight or
but slightly arched; the dorsal is quite convex.  The anterior and
posterior extremities are equally rounded.  The peristome begins as
a small depression, but becomes larger until it takes in nearly all
of the ventral surface. The depression becomes much deeper at about
the center of the body, and is especially marked on the left side of
the peristome. In this deeper portion is the mouth, with an almost
imperceptible oesophagus. Upon the left edge of the peristome is a
high, undulating membrane, sail-like in appearance when extended.
This may stretch around the posterior edge of the peristome and upon
the right aide, thus forming a pocket by means of which the food
particles are directed into the mouth. The rest of the right edge
of the peristome is occupied by closely approximated powerful cilia
(Bütschli) or a second undulating membrane (Stein). The body cilia
are relatively long. Trichocysts and caudal bristles may be present.
The contractile vacuole is subterminal and dorsal; it is questionable
whether there are canals leading to it. A round macronucleus with
one micronucleus is in the anterior half of the body. The anus is
terminal. Food is chiefly bacteria. Movement combines springing with
swimming and rotation. Fresh and salt water.


Pleuronema chrysalis Ehr., sp.  Fig. 40.

Synonyms: _Pleuronema crassa_ Dujardin '41; _P. marina_ Duj. '41;
Fabre-Domergue '85; _P. coronata_ Kent '81; _Paramoecium chrysalis_
Ehr. '38; _Lembadion orale_ G. & R. '88; _Histiobalantium agile_
Stokes '85, '88.

The body is ovoid, slightly flattened, rounded at both ends, the
anterior end sharper than the posterior. The ventral surface is
almost entirely taken up by a peristome which extends from the
anterior end posteriorly three-quarters of the body length. The
posterior end of the peristome is straight, the left curved,
following the depressed portion. The body is covered with fine cilia
in longitudinal lines, except on the peristome. The mouth is small
and situated in the hollow of the peristome near the left border. On
the left peristome edge is a large undulating membrane. It begins
near the anterior end of the body and increases in height posteriorly
following the peristome edge around on the right side. This posterior
bend of the membrane causes the appearance of a full sail, so
often seen. It can be entirely withdrawn and folded together in
the peristome. On the right edge of the peristome are large,
powerful cilia. The contractile vacuole is central and dorsal; the
macronucleus is in the anterior half of the body, with one attached
micronucleus. Food consists of bacteria. Not very common. Fresh
and salt water. It often remains quiet, with membrane and cilia
outstretched, as though dead, but suddenly gives a spring and is
gone.


[Illustration: Fig. 40.--_Pleuronema chrysalis_.]


Pleuronema setigera, n. sp.  Fig. 41.

Body colorless, elongate, and with the general form of a cucumber,
the posterior end being somewhat pointed. The mouth and relatively
small peristome are situated in the lower third of the body. The
peristome begins as a shallow furrow at the center of the ventral
surface and dips sharply into the buccal depression, which is deep
and turned toward the posterior end. The left edge of the peristome
bears a high undulating membrane, which extends anteriorly only
as far as the center of the body; posteriorly it passes around to
the right edge of the peristome, thus forming the characteristic
membranous pocket. Inside the oral depression is a second undulating
membrane, running down to the mouth. This is small and without an
oesophagus. The body is clothed with long setose cilia which are
frequently fully outstretched when the animal is resting, a slight
tremor of the large membrane alone indicating vitality. Posteriorly
these appendages are drawn out into long filiform setæ, the number
varying in different individuals from three to nine or ten. These
are extremely fine and difficult to see without a high power (_e.g._
1/12 oil) and careful focussing of the substage condensor. Like _P.
chrysalis_, the resting periods are terminated by sudden springs,
otherwise the movements are steady and forward. The macronucleus is
central, and the contractile vacuole posterior and terminal. Length
45µ to 50µ; greatest diameter 17µ. In decaying algæ.

It was this form, I believe, that Peck '95 described as a "ciliate."


[Illustration: Fig. 41.--_Pleuronema setigera_.]


Genus LEMBUS Cohn '66.

(Cohn '66; Quennerstedt '69; Kent '81; Fabre-Domergue '85; Gourret &
Roeser '88; Bütschli '88; Shevyakov '96.)

Free-swimming animals of elongate form, more or less elastic, and
flexible, bending readily to avoid obstacles, etc. The anterior half
is usually drawn out into a slightly curved neck-like portion. The
peristome is a small groove leading from the anterior end to the
mouth about midway down the ventral side of the body. Bütschli,
following Quennerstedt, describes an undulating membrane on each side
of the peristome groove. Other observers, however, usually describe
but one, the left, which is clearly defined and stretches out some
distance from the body, while the right border is described as having
smaller but very active cilia. The general body surface is clothed
with fine, uniform cilia, and body striæ are usually absent. One
or more caudal bristles may be present. The contractile vacuole is
posterior and terminal, and may be multiple. The macronucleus is
spherical and perhaps double (Kent). Food is chiefly bacteria, and
the animals are frequently found with the anterior end embedded in
zoogloea masses. Salt water, usually in infusions.


Lembus infusionum, n. sp. Fig. 42.

The body is elongate, lancet-shaped, with a tapering anterior
extremity. The dorsal outline is concave through the bending of the
anterior end, while the ventral outline presents an even, convex
curve. The mouth lies slightly above the center of the body and marks
the posterior limit of the ventral peristomial groove, which curves
slightly from the anterior extremity. Each side of this groove bears
an undulating membrane, the left being much larger and conspicuously
striated. The general form of this left membrane is triangular,
the widest part is anterior, the narrowest at the mouth. The
right membrane is similar in form, but smaller and more active.
The endoplasm is colorless and finely granular, not regionally
differentiated. The ectoplasm consists of a relatively thick cortical
plasm specially noticeable in the posterior half of the body and
a delicate cuticle which bears almost imperceptible longitudinal
markings--the insertion points of the fine cilia. The body is covered
with uniform cilia except at the anterior extremity. Here they are
much larger and bristle-like. I was unable to find any cilia in the
peristome. One long caudal bristle, one-quarter of the length of the
body, trails out behind. The macronucleus is spheroidal and placed
near the center of the body; a conspicuous micronucleus lies near it.
A row of contractile vacuoles extends from the posterior end. I have
seen as many as six of nearly equal size and one or two smaller ones.
The intervals of contraction are quite long. Length 70 to 75µ;
greatest diameter 10 to 12µ.

_L. infusionum_ resembles _L. elongatus_ in its general form and in
its mode of life, for it excavates a retreat in zoogloea masses and
lies there for considerable periods perfectly quiet. It differs
from _L. elongatus_ and from _L. velifer_ (probably the same as _L.
elongatus_ of Claparède & Lachmann) in the presence of the caudal
bristle, in the absence of annular markings, number of contractile
vacuoles, and in the slightly smaller size. It resembles _Lembus
verminus_ (Müller) as described by Kent (_Proboscella vermina_), and
_L. intermedius_ as described by Gourret & Roeser (_Lembus verminus_
syn.)in the absence of annular markings and in the presence of a
caudal bristle. It differs from the former, however, in the absence
of a tentacle-like process, and from both in the absence of a double
nucleus and in the presence of many vacuoles. These features are so
characteristic of all the specimens examined that I have concluded,
somewhat reluctantly, to give it a specific name. It is common in old
infusions of algæ, especially after decomposition is well advanced.
Its food consists of bacteria.


[Illustration: Fig. 42.--_Lembus infusionum_.]


Lembus pusillus Quennerstedt 1869.  Fig. 43.

Synonym: _L. subulatus_ Kent 81.

This species is much smaller than the preceding, and might easily
be mistaken for _Uronema marina_. It is subcylindrical in form, the
anterior end bluntly pointed, the posterior end rounded. The oral
apparatus is quite different from _Uronema_. The mouth, as in the
preceding species, is at the end of a long peristomial groove
extending from the anterior end to the middle of the body. The edges
of the peristome bear undulating membranes as in _L. infusionum_.
Like the latter, there is one caudal bristle, but unlike it there is
only one posterior contractile vacuole, while the endoplasm is filled
with large granules or food balls. The cuticle is distinctly striated
with longitudinal markings, and the cilia are uniform in length.

Habitat similar to that of _L. infusionum_, in zoogloea masses.
Length 26 to 30µ; diameter 7 to 8µ.

Although Quennerstedt's description of _L. pusillus_ makes no mention
of a caudal bristle, the size and other characters are so closely
similar that I hesitate to make a new species. The bristle is
extremely delicate, scarcely thicker than a cilium, and easily
overlooked, yet with proper focussing of the condenser I found it on
every specimen examined.


[Illustration: Fig. 43.--_Lembus pusillus_.]


KEY TO MARINE GENERA OF OPALINIDÆ.

Diagnostic characters: The form is oval, and the body may be short or
drawn out to resemble a worm. They are characterized mainly by the
absence of mouth and pharynx.

Anterior end not pointed; body            Genus *_Anoplophrya_
cylindrical; tapering

Anterior end pointed; body elongate;      Genus _Opalinopsis_
cylindrical; tapering

   * Presence at Woods Hole indicated by asterisk.


Genus ANOPLOPHRYA Stein '60.

(Stein '60; Claparède '60; Leidy '77; Vejdovsky '79; Kent '81;
Balbiani '85; Bütschli '88; Shevyakov '96.)

The general form is elongate, cylindrical or slightly flattened, with
rounded ends, the posterior end tapering. The body is striated with
clearly defined, often depressed lines, which run longitudinally and
sometimes spirally. The contractile vacuoles are usually placed in
rows upon the edges. The macronucleus is almost always long and
band-formed, rarely oval, and generally extending through the entire
length of the body. Micronuclei have been made out in one case.
Reproduction is effected by simple cross division or by budding at
the posterior end, and is frequently combined with chain formation.
The main characteristic is the entire absence of mouth and
oesophagus, the animals being parasitic in the digestive tract of
various annelids. Parasites, salt-water forms.


Anoplophrya branchiarum. Stein '52.  Fig. 44.

_A. circulans_ Balbiani.

The body is cylindrical to pyriform, in the latter case broadened
anteriorly. Cuticle distinctly marked by longitudinal striations
which take the form of depressions and give to the body a
characteristic melon shape. The endoplasm contains a number of large
refringent granules--probably body products. The nucleus is elongate,
somewhat curved, and coarsely granular. A micronucleus lies in the
concavity. The cilia are long, inserted rather widely apart along
the longitudinal markings. The contractile vacuole is single and
is located at the pointed end, which is directed backwards during
locomotion. One specimen found free swimming among some algæ.

Length 104µ; greatest diameter 36µ.

I was much surprised to find this form swimming about freely in the
water; its mouthless condition showed it to belong to the family of
parasites, the _Opalinidæ_. As the name indicates, however, this
species is an ectoparasite upon the gills, and Stein gave the name
_branchiarum_ to a fresh-water form parasitic upon _Gammarus pulex_.
The Woods Hole form is so strikingly similar to the figure of _G.
branchiarum_ that, although the name was given to a fresh-water form,
it obviously applies to this marine variety. One important difference
is the presence of only one contractile vacuole in the marine form.


[Illustration: Fig. 44.--_Anoplophrya branchiarum_.]


KEY TO FAMILIES OF HETEROTRICHIDA.

Cilia cover the body                      1

Cilia reduced to certain                  2
localized areas

1. _Polytrichina_.

   a. The mouth terminates a long         Family _Plagiotomidæ_
      peristomial furrow having an
      adoral zone along the entire
      left edge

   b. Peristomial area a broad            Family _Bursaridæ_
      triangular area ending in mouth

   c. Peristomial depression short;       Family _Stentoridæ_
      limited to the anterior end; its
      plane at right angles to the
      long axis of body; surface of
      peristome striated and ciliated;
      no undulating membranes

2. _Oligotrichina_.

   a. Peristome without cilia; cilia      Family _Halteriidæ_
      limited to one or more girdles
      about body

      One marine genus                    *_Strombidium_

   b. Thecate forms; the body is          Family _Tintinnidæ_
      attached by a stalk to the cup;
      within the adoral zone is a ring
      of cilia.

   c. The peristomial depression is       Family _Ophryoscolecidæ_
      deep and funnel-like; cuticle
      thick, with posterior spine-like
      processes.

   * Presence at Woods Hole indicated by asterisk.


KEY TO THE MARINE GENERA OF PLAGIOTOMIDÆ.

Diagnostic characters: The peristome is a narrow furrow which begins,
as a rule, close to the anterior end and runs backward along the
ventral side, to the mouth, which is usually placed between the
middle of the body and the posterior end. A well-developed adoral
zone stretches along the left side of the peristome, and is usually
straight.

1. Body cylindrical; size medium;         Genus _Metopus_
   peristome long and turns sharply
   to the left at the extremity

2. No torsion in the peristome;           Genus _Blepharisma_
   undulating membrane is confined
   to the posterior part of peristome

3. No peristomial torsion;                Genus _Spirostomum_
   body highly contractile;
   no undulating membrane


KEY TO THE MARINE GENERA OF BURSARIDÆ.

Diagnostic characters: The body is usually short and pocket-like, but
may be elongate. The chief characteristic is the peristome, which is
not a furrow, but a broad triangular area deeply insunk and ending in
a point at the mouth. The adoral zone is usually confined to the left
peristome edge, or it may cross over to the right anterior edge.

1. The anterior half of the body          Genus _Balantidium_
   tapers to nearly a point in front;
   the peristome is narrowest at the
   apex; the mouth is the entire
   peristome base.

2. The anterior end does not taper;       Genus *_Condylostoma_
   the peristome is widest at the end
   of the body; the mouth is clearly
   defined.

   * Presence at Woods Hole indicated by asterisk.


Genus CONDYLOSTOMA (KONDYLOSTOMA Bory de St. Vincent 1824) Dujardin
'41

(Dujardin '41; Claparède & Lachmann '58; Stein '59, '67; Cohn '66;
Quennerstedt '67; Wrzesniowski '70; Bütschli '76, '88; Kent '81;
Maupas '83; Shevyakov '96.)

Colorless and more or less flexible animals of medium size. The
general form is elongate and cylindrical or somewhat smaller
anteriorly. The posterior end is broadly rounded, the anterior end
somewhat truncate and oblique. The peristome is broad and triangular,
the base of the triangle being the entire anterior end of the body.
The entire length of the peristome is one-fourth or less of the body
length. The mouth is large and placed at the apex of the peristomial
triangle and opens into a comparatively small oesophagus. The right
edge of the peristome is lamellate and bears a clearly defined
undulating membrane. The adoral zone is well developed upon the left
edge of the peristome, from which it passes around anteriorly to the
right edge. The surface of the peristome is free from cilia, but
the rest of the body is uniformly coated with small active cilia.
Contractile vacuoles are not safely determined. Bütschli thinks
there is probably one terminal vacuole, but some observers deny this
(_e.g._ Maupas). Others describe them on the dorsal side of the
posterior end (Quennerstedt). The macronucleus is long and beaded and
placed upon the right side. Micronuclei are numerous and scattered
along the macronucleus. The anus is terminal and dorsal. Food
consists of large and small particles. Movement rapid, free swimming,
alternating with resting periods; in some cases an undulating or
wriggling movement is seen, showing clearly the flexibility of the
body. Fresh and salt water.


Condylostoma patens Müller.  Fig. 45.

The body is elongate, somewhat sac-like, five or six times as long
as broad, plastic, and frequently contains brightly colored food
granules. The triangular peristome takes up the greater part of the
anterior end, and the mouth is situated at the sharper angle of the
triangle, about one-fourth of the total length from the anterior end.
The cuticle is longitudinally striated, the lines having a slightly
spiral course. They are not closely set, and fine cilia are thickly
inserted along their edges. The endoplasm is granular and viscous.
The motile organs consist of an adoral zone of membranelles, which
stretch along the left edge of the peristome and the front edge of
the body. The right edge of the peristome supports an undulating
membrane. The nucleus is moniliform and extends the full length of
the left side; a number of micronuclei are distributed along its
course (Maupas).

Length 400µ; diameter at widest part 105µ. Maupas gives the length
from 305µ to 495µ; and Stein 376µ to 564µ. Very common.

For a more extended account of the structures, see the excellent
description by Maupas '83.


[Illustration: Fig. 45.--_Condylostoma patens_.]


KEY TO THE MARINE GENERA OF STENTORIDÆ.

Diagnostic characters: The peristome is relatively short and limited
to the front end of the animal, so that its plane is nearly at right
angles to that of the longitudinal axis of the body. The adoral zone
of cilia either passes entirely around the peristome edge or ends at
the right-hand edge. The surface of the peristome is spirally
striated and provided with cilia. Undulating membranes are absent.

1. Peristome circular in outline;         Genus _Stentor_
   limited to the anterior end

2. The peristome is drawn out into two    Genus _Folliculina_
   wing-like processes; tube-dwelling


Genus STROMBIDIUM Cl. & Lach. '58.

(Stein '67; Bütschli '73; Fromentel '74; Kent '81; Gruber '84; Entz
'84; Maupas '83. Bütschli '88.)

Small, colorless (except for ingested food) animals with
characteristic springing movements. The form is usually constant, but
in some cases may be plastic like _Astasia_; it is usually globular
or conical, the posterior end being more or less pointed, the
anterior end broadest. The latter is surrounded by a complete circle
of the adoral zone, the oral end of which passes into a peristomial
depression which extends deep into the middle of the body. The mouth,
with a very small oesophagus, lies at the bottom of the inturned
peristome. The region surrounded by the adoral zone is frequently
drawn out into an anterior process, occasionally bearing a pigment
mass. The ventral surface in some cases bears cilia, which may be
distributed or restricted to a row of large cilia. Trichocysts are
usually present and may be widely spread, limited to the posterior
region, or arranged in a girdle about the middle. The contractile
vacuole is simple, and posterior in position. The macronucleus
is spherical and usually central in position. Movement is rapid
swimming, combined with resting and floating periods, the latter
usually terminated by a sudden leap.

Fresh and salt water; more common in the latter.


Strombidium caudatum Fromentel '74.  Fig. 46, a, b, c.

Fromentel described a fresh-water form of this genus with a caudal
appendage. The body is pyriform, broadly truncate on the anterior
end, in the middle of which rises a papilliform process (Schnabel).
On this process is a heap of pigment granules, which, however, are
not constant. A ring of long cirri surround the anterior end and pass
into the peristome, and from the left edge of this line of cirri a
large adoral zone continues down to the mouth. The peristome is
elongate and sac-form, and the mouth lies at the posterior extremity.
With the exception of a caudal filament there are no other motile
organs; this is about half as long as the body, structureless,
hyaline, and sharply pointed. It splits up into a bundle of fine
fibers upon treatment with caustic potash (c). The cirri emerge from
minute hollows in the edge of the anterior border. The cortical
plasm contains peculiar rod-like bodies, which look more like lines
or markings than like rods or trichocysts. The nucleus is large,
spherical, and placed in the center of the body. The contractile
vacuole is posterior.

Length without appendage is about 35µ; greatest diameter 15 to 18µ.
In decaying vegetable matter. Common.


[Illustration: Fig. 46.--_Strombidium caudatum_.]


Although Fromentel's species is incompletely described, it is very
evident that the organism corresponds fairly well with the Woods Hole
variety. His was a fresh-water type; this is marine, but the caudal
filament and the contractile vacuole are similar. Certainly in this
case the organism can not be regarded as a Vorticella broken off its
stalk, as Kent '81 suspected. The anterior process with its pigment
spot; the cirri, the spherical nucleus, the position of the vacuole,
etc., are all opposed to such an interpretation which Kent applied to
the original species. Neither can it be a Tintinnoid. I place it
provisionally as _S. caudatum_.


KEY TO THE MARINE GENERA OF TINTINNIDÆ.

Diagnostic characters: Body attached by a stalk to a cup. Inside the
zone of membranelles is a ring of cilia (par-oral).

1. The test is gelatinous and more or     Genus _Tintinnidium_
   less covered by foreign particles

2. The test is chitinous and clear.       Genus _Tintinnus_
   No foreign particles.

3. The test is chitinous; covered by      Genus *_Tintinnopsis_
   foreign particles, growth rings
   frequent

4. The test is chitinous, often           Genus _Codonella_
   covered by foreign particles.
   The test is marked by discoid,
   circular, or hexagonal spots.

5. The test is perforated by pores        Genus _Dictyocysta_
   of circular or hexagonal form.

   * Presence at Woods Hole indicated by asterisk.


Genus TINTINNOPSIS Stein '67.

(Stein '67; Kent '81; Daday '87; Bütschli '88.)

Medium-sized ciliates, inclosed in a chitinous lorica with embedded
sand crystals. The form of the house, or lorica, varies greatly.
In some cases the mouth opening is wide, giving the lorica a bell
form; it may be long and tubular, short and spherical, or variously
indented. The animal is attached, as in the closely allied genus
_Tintinnus_, by a peduncle to the bottom of the lorica. The anterior
end of the animal is inclosed by two complete circles of cilia;
one, the outer, forming the adoral zone, is composed of thick
tentacle-like membranelles, the other consists of shorter cilia
within the adoral zone. The mouth leads into a curved oesophagus
containing rows of downward-directed cilia (Daday). The entire body
is covered with cilia, but as the lorica is always opaque these can
be made out only when the animal is induced to leave the house. The
only difference between this genus and _Tintinnus_ is the covering
of foreign bodies--usually sand crystals. Movement is rapid and
restless, and peculiarly vibratory, owing to the apparent awkwardness
in moving the house.  Salt water.


Tintinnopsis beroidea Stein, var. plagiostoma Daday.  Fig. 47.

Synonym: _Codonella beroidea_ Entz '84.

The shell is colorless, thimble-shaped, with a broadly rounded
posterior end. The body is cylindrical. The internal organs were not
observed. Membranelles 24 in number. Length 50µ; greatest diameter
40µ.


[Illustration: Fig. 47.--_Tintinnopsis beroidea_.]


Var. compressa Daday '87.

The posterior end of the shell is pointed, the lower third of the
shell is swollen, the upper third is uniform in diameter and without
oral inflation or depression. Nucleus not seen.

Length 70µ; greatest diameter 48µ.


Tintinnopsis davidoffi Daday.  Fig. 48.

The shell is large, elongated, and provided with a considerable
spine. The chitin of the shell is covered with silicious particles of
diverse size. The internal structures were not observed.

Length of shell and spine 230µ; diameter of the oral aperture 54µ.


[Illustration: Fig. 48.--_Tintinnopsis davidoffi_.]


The variations of these species are considerable, and as the internal
structures, such as the nucleus, are essential in fixing their
systematic position, I place them as above, provisionally, and until
further observations can be made.


KEY TO FAMILIES OF HYPOTRICHIDA.

a. Peristome indistinct; cilia on         Family _Peritromidæ_
   ventral surface uniform and not        One genus, *_Peritromus_
   differentiated into cirri

b. Peristome more or less indistinct;     Family _Oxytrichidæ_
   cilia reduced to a few rows on the
   ventral surface; anal and frontal
   cirri present

c. Cilia entirely reduced; frontal        Family _Euplotidæ_
   and anal cirri present or reduced;
   macronucleus band-formed or spherical

d. Peristome reduced to left edge and     Family _Aspidiscidæ_
   does not reach over the anterior       One genus, *_Aspidisca_
   margin

   * Presence at Woods Hole indicated by asterisk.


Genus PERITROMUS Stein '62.

(Stein '62, '67; Maupas '83.)

The body is flat, colorless or tinged with yellow, and contractile.
It is elliptical in outline, with broadly rounded ends; in some
cases the left edge is slightly incurved, the right edge convex.
The ventral surface is flat, the dorsal surface is arched in the
middle region of the body. The edges being flat are somewhat more
transparent than the remainder of the body. The ventral surface is
striated by longitudinal straight or slightly curved lines, the
dorsal surface is smooth and without cilia. (Maupas describes
bristles on the back, but this is not corroborated.) The adoral zone
is fairly well developed, but not distinctly marked off from the
remaining ventral surface. It begins on the right side and extends
entirely around the frontal margin and down the left side below the
middle of the body, where it turns suddenly to the right, entering
the slightly insunk peristome. The mouth leads into a short,
indistinct oesophagus. One contractile vacuole is situated in the
dorsal swelling at the posterior end of the animal. Macronucleus
double, one in each side of the dorsal swelling. Movement is slow
and creeping, with a peculiar method of contracting the more hyaline
edge, which may turn upward or around a foreign object.

Fresh (?) and salt water.


Peritromus emmæ Stein.  Fig. 49.

With the characters of the genus.


[Illustration: Fig. 49.--_Peritromus emmæ_, ventral and lateral
aspects.]


KEY TO THE MARINE GENERA OF OXYTRICHIDÆ.

Diagnostic characters: The peristome is not always marked off from
the frontal area. In the most primitive forms the cilia on the
ventral surface are similar to those of the preceding family
(_Peritromidæ_). Usually some of the anterior and some of the
posterior cilia are fused into cirri, distinguished as the frontal
and anal cirri, respectively. In the majority of forms all of the
cilia are thus differentiated; strong marginal cirri are formed in
perfect rows, and ventral cirri in imperfect rows. In addition to the
adoral zone there is an undulating membrane on the right side of the
peristome, and in some cases a row of cilia between the membrane
and the adoral zone. These are the par-oral cilia and they form the
par-oral zone.

1. The posterior end is pointed or        2
   tail-like

   The posterior end is rounded;          5
   not tail-like

2. The front end is pointed               3

   The front end is rounded               4

3. Frontal and anal cirri absent;         Genus _Stichotricha_
   often tube-forming

   Eight frontal and 3 caudal cirri;      Genus _Gonostomum_
   not tubiculous

4. Anal cirri present; with or            Genus *_Epiclintes_
   without short lateral bristles

   Anal cirri absent; no bristles         Genus _Uroleptus_

5. With frontal cirri                     6

   No frontal cirri; 2 to 3 rows of       Genus _Holosticha_
   ventral cirri; anal cirri small

6. Right margin of peristome straight     Genus _Oxytricha_
   as far as the anterior end; 5 rows
   ventral cirri; 5 anal cirri

   Right margin of peristome curved       7

7. Five rows or less of ventral cirri     8

   More than 5 rows of ventral cirri      Genus _Urostyla_

8. Membranelles normal; 5-10 anal         Genus *_Amphisia_
   cirri; no caudal cirri

   Membranelles normal; 5 to 10 anal      Genus _Stylonychia_
   cirri; 3 caudal cirri

   Membranelles very large and            Genus _Actinotricha_
   powerful; adoral zone not
   continued to mouth; 5 anal cirri

   * Presence at Woods Hole indicated by asterisk.


Genus EPICLINTES Stein '62.

(Stein '62, '64, '67; Mereschowsky '79; Gruber '87; Bütschli '88.)

Very active, contractile, colorless forms of rather small size. In
the fully expanded condition the body is oval and long, with its
greatest width in the center or at the front half of the body. The
posterior end is always drawn out into a relatively long tail, which
is extremely elastic. The peristome is short and stretches around the
front end of the animal. In the frontal region are from one to three
rows of cirri. The ventral surface is covered with longitudinal rows
of cilia, the number of rows being in dispute (6 to 7 according to
Stein; 9 according to Mereschowsky and Rees) Some of these cilia
project from the lateral edges and from the posterior end, where
they are slightly elongated. The anus is dorsal and placed at the
beginning of the posterior process. Macronucleus probably double.
Movement is rapid and restless, the tail process contracting to jerk
the body backward. Salt water.


Epiclintes radiosa Quenn.  Fig. 50.

Synonym: _Metra radiosa_ Quenn.

The body is elongate, slightly narrowed anteriorly, and drawn out
posteriorly into a long, retractile, tail-like portion. Five large
cirri extend outward from the anterior extremity. The caudal portion
may be extended to a distance equal to twice the length of the body
or contracted to half the length. The peculiar nervousness of this
form made it extremely difficult to study, and the oral region was
imperfectly made out. The anterior cirri appear to line the upper
left border of the peristome, which is marked by a row of large
cilia. The peristome begins upon the right side of the anterior end
and passes backward and to the left, narrowing at this point. The
mouth is very small and difficult to see. It is apt to stay in
one locality under zoogloea, switching back and forth with great
vivacity, or hanging on by the posterior cilia while the anterior
end stretches out in the surrounding medium. Nucleus and contractile
vacuole were not observed. Length 45µ.


[Illustration: Fig. 50.--_Epiclintes radiosa_.]


Genus AMPHISIA Sterki '78.

(Sterki '78; Kent '81; Bütschli '88.)

The body is plastic and soft, colorless or slightly tinged with
yellow or red. In form it is oval or elongate, the posterior end
is rounded and slightly reduced in diameter, but does not form a
distinct tail. The anterior end is also rounded and similarly reduced
in width. There are two rows of marginal cirri (_Randcirren_), which
may be placed some distance from the edge, and two or three rows of
ventral cirri between them. There are from 3 to 5 frontal cirri of
larger size than those of the ventral rows, and from 5 to 10 anal
cirri. (The genus _Holosticha_ is similar in all respects save
the presence of frontal cirri.) The macronucleus is double; the
contractile vacuole is central and on the left side. The peristome
is long and rather narrow and carries an undulating membrane on its
right margin. Fresh and salt water.


Amphisia kessleri Wrzes. '77.  Fig. 51.

Synonyms: _Trichoda gibba_ Müller; _Oxytricha gibba_ Stein '59; _O.
velox?_ Quen. '69; _O. kessleri_ Wrzes. '77.

Body elongate, slightly sigmoid and swollen in the center, about
3-1/2 times as long as broad; the rounded anterior end is turned to
the left, the similarly rounded posterior end to the right; both ends
taper slightly. The peristome is long and narrow, with a distinct
adoral zone which appears broken in its course. To the right of this
adoral zone is a single line of preoral cilia. On the right border of
the peristome is an undulating membrane. The three frontal cirri form
a triangle and the five smaller anal cirri form a continuous line
with the broken row of ventral cirri. There are two and one-half rows
of ventral cirri and the marginal cirri are drawn in until they are
ventral in position.

Length 135µ; greatest width 40µ.


[Illustration: Fig. 51.--_Amphisia kessleri_.]


This variety differs from _O. kessleri_ as described by Wrzesniowski
in having three frontal cirri instead of four. Another difference
is in the structure of the nuclei and in their position. These
differences are too minute to warrant a specific name. _O. velox_ of
Quennerstedt is probably the same as _0. kessleri_, but differs in
having three complete rows of ventral cirri. _O. velox_ has three
frontal cirri in a line, thus differing from the Woods Hole form.


KEY TO THE MARINE GENERA OF EUPLOTIDÆ.

Diagnostic characters: Cilia, as well as the frontal, marginal, and
ventral cirri, very much reduced; the anal cirri, on the other hand,
are always present. The macronucleus is band-form.

1. Frontal cirri more than 8              2

   Frontal cirri less than 8              3

2. Eleven marginal cirri on the left      Genus _Certesia_
   side; 11 frontal cirri

   Four marginal cirri, 2 on each         Genus *_Euplotes_
   side; 9 to 10 frontal cirri

3. Seven frontal, 5 anal, 3 right         Genus *_Diophrys_
   marginal, and 2 left marginal
   cirri

   No frontal, 5 anal, 3 right,           Genus *_Uronychia_
   and 2 left marginal cirri

   * Presence at Woods Hole indicated by asterisk.


Genus EUPLOTES (Ehr. 1831) Stein '59.

(Ehrenberg '31, '38; Stein '59; Cl. & Lach. '58; Quennerstedt '65,
'67, '69;  Bütschli '88; Kent '81; Gourret & Roeser '88; Möbius '88.)

Small to medium-sized forms. Rigid in form, colorless, or green by
chlorophyl. They are quite flat on the ventral surface but decidedly
arched dorsally, and the contour is usually oval. The anterior end is
broadly rounded to truncate; the posterior end is similarly rounded,
or may be somewhat pointed. The mouth is placed centrally or near
the left margin, and from it the right edge of the peristome forms a
curved line to the left, which bends forward, thus making the greater
part of the left edge the peristomial area. In front the peristome
bends sharply to the right and extends as far as the right end of the
adoral zone. Upon the frontal and median ventral surface are 9 to 10
great cirri (_Bauchwimpern_ of Stein). Posteriorly five great anal
cirri stretch out beyond the posterior body margin. In addition to
these there are two smaller marginal cirri upon the left body edge,
and two similar ones on the hinder part of the body. The dorsal
surface is rarely smooth, but usually is marked by longitudinal
ridges, and rows of dorsal bristles have been described. The single
contractile vacuole lies on the right side in the region of the
anal cirri, sometimes just above them, sometimes below. The anus is
posterior and on the right side. The characteristic macronucleus is
long and band-form, its main portion being usually on the left side
with an anterior and a posterior arm toward the right. Movement is
rapid swimming, which, however, is frequently broken by creeping
periods, during which the animals appear to be examining the foreign
body on which they creep.

Fresh and salt water.


Euplotes charon Ehr.  Fig. 52.

Synonyms: _Trichoda charon_ Müller; _Ploesconia charon_; _P.
affinis_, _subrotunda_, _radiosa_, _longiremis_, Dujardin '41.

The body is oval, small, and somewhat variable in length. The
carapace is strongly marked upon the dorsal side by deep longitudinal
grooves, 6 to 8 in number; the grooves may be absent, however. The
adoral zone extends to the posterior third of the body, the mouth
and oesophagus are directed anteriorly. There are 10 ventral cirri,
7 of which are on or near the frontal border and 3 near the right
edge. There are 5 posterior cirri and 4 anal cirri, of much smaller
size. The cirri may or may not be fimbriated, the latter condition
indicating the approaching disintegration of the body and is
abnormal. The macronucleus is long and band-formed or horseshoe
shape. The contractile vacuole lies on the right side dorsal to the
posterior cirri.

Fresh and salt water. Length 45µ; diameter 25µ.


[Illustration: Fig. 52.--_Euplotes charon_, dorsal and ventral
aspects.]


Euplotes harpa Stein.  Fig. 53.

The body is elongate, oval, somewhat widened anteriorly, and has
rounded ends. The frontal margin is three-toothed. Ten ventral cirri.
Dorsal surface provided with 8 longitudinal markings. The peristome
is long and broad, with considerable variation. The adoral zone
consists of powerful membranelles arranged in a continuous curve
from the mouth to the extreme right frontal margin. Seven of the 10
ventral cirri are situated at the anterior extremity; the remainder
are arranged in a triangle on the right edge. The anal cirri, 5 in
number, are long and stiff; the marginal cirri smaller and finer. The
nucleus and contractile vacuole are similar to those of the preceding
species.

Length 95µ; width 54µ.


[Illustration: Fig. 53.--_Euplotes harpa_.]


Genus DIOPHRYS Dujardin '41.

(Bütschli '88.)

Medium size, colorless to yellow, rigid in form. The body contour
is oval, the anterior end being rounded or slightly reduced, the
posterior end usually cut in on the right side. The peristome is
broad but less extensive than in _Euplotes_, and may extend beyond
the middle of the body. Its right edge is convex toward the right
side, extends forward and does not turn again to the right. The
anterior ventral surface has 7 to 8 scattered cirri and just behind
the mouth is a transverse row of large anal cirri. In the sharp
in-cut of the posterior end are three great angular cirri. Two
lateral cirri are placed on the left of the median line between
the mouth and the anal cirri, and usually in a slight hollow. The
contractile vacuole is on the right side in the vicinity of the
anal cirri. The macronucleus is in two parts, each band-form, one
anterior, the other posterior in position. Movement is rapid and
steady. Salt water.


Diophrys (Styloplotes) appendiculatus Stein '59.  Fig. 54.

Synonyms: _Styloplotes appendiculatus_ Stein '59; Kent '81;
Quennerstedt '67, etc.

The general form resembles _Euplotes_. Its outline is oval and
regular except at the posterior end on the right side, where there is
a considerable indentation. The frontal margin is characterized by a
row of powerful membranelles, which become smaller at the peristome
and at the mouth they are of characteristically small size. The
ventral cirri are 7 in number. Five of them are in one row from the
anterior end down the right side nearly to the anal cirri; 1 is on
the frontal border between the first two; 1 lies just anterior to the
second anal cirrus from the right side. The 5 anal cirri are large
and powerful and extend some distance beyond the posterior end of the
body. In all specimens observed these cirri curve to the left. Dorsal
to the anal cirri and placed deep into the dorsal pit are 3 large,
sharply curved cirri, which in most cases are fimbriated, but when
the specimens are normal these are pointed and curve abruptly to the
right. Two smaller cirri lie to the left of the group of anal cirri.
The peristome is well-marked by the adoral zone, and upon its right
border there is a row of cilia, and a similar row of cilia runs along
the base of the oral membranelle. The macronucleus is double and
consists of two elongate cylindrical masses lying parallel with
one another. One of these is in the anterior region; the other is
posterior. The contractile vacuole lies dorsal to the anal cirri
and anterior to the three dorsal cirri. The movement and general
activities resemble those of _Euplotes_.

Length 50µ; diameter 25µ.


[Illustration: Fig. 54.--_Diophrys appendiculatus_.]


Genus URONYCHIA Stein '52.

(Stein '59, '67; Quennerstedt '67; Kent '81; Bütschli '88.)

Medium-sized colorless ciliates of usually constant body form. The
body is somewhat short and oval in outline. The anterior end is
broadly truncate, the posterior end rounded or slightly pointed. The
ventral and dorsal surfaces are considerably arched and the latter
usually has a number of rows of longitudinal stripes. The open
peristome is broad and reaches back to the middle of the ventral
surface and beyond. According to Stein, the two edges can approach
each other, thus opening and closing the peristomial area. Its right
edge forms a greater angle with the front edge than in the genus
_Euplotes_, and the left edge forms a greater angle with the front
edge than in that genus. The left edge also appears to cover over the
adoral zone slightly. There are no ventral cirri in front, but on the
posterior ventral surface are 7 great springing cirri. Five of these
are inserted on the right aide in a deep in-sinking, and the other 2
in a similar depression on the left ventral surface. Above the 5
right-side cirri, _i.e._, dorsal to them, but in the same depression,
are 3 angular cirri. A few edge cirri are found to the left of them
and another to the right of the 5 cirri. The contractile vacuole is
on the left side between the main groups of cirri. The macronucleus
is band-form or spherical, and is situated in the middle region of
the body. Movement consists in forward swimming with sudden springs.

Salt water.


Uronychia setigera, n. sp.  Fig. 55.

This species is very common in the Woods Hole waters. It is small,
colorless, and very active. The most characteristic feature is
the posterior end with its relatively enormous cirri, which are
apparently large enough for an animal four times its size. The form
is ovoid, widened posteriorly.

The ventral surface is flat and has two excavations in the posterior
end. The right hollow is larger and contains 5 great cirri of unequal
size, the extreme right one being the largest. The left hollow
contains 2 cirri, also of dissimilar size. Dorsal to the 5 right
cirri are 3 sickle-formed cirri, which are usually fimbriated. These
are pointed and curve regularly to the left. The peristome is wide
and open, and a small pocket-like hollow on its left border indicates
the region of the mouth. The adoral zone runs into this pocket
and the mouth is located in its lower right-hand corner. In _U.
transfuga_ the right border is generally described as having a
membrane of extreme delicacy. I was unable to see such a membrane in
this form, but in its place there are 2 flagella-like cirri extending
from the margin of the mouth-opening into the peristome, and these
vibrate slowly. I do not believe these could be the moving edge of an
undulating membrane, for they are quite distinct. The macronucleus is
spherical instead of band-form, and a single micronucleus is closely
attached. This is unlike the European species _U. transfuga_, in
which the nucleus is elongate. The contractile vacuole lies between
the two sets of posterior cirri. There are no marginal folds like
those of the European species.

Length 40µ; width 25µ. Common.


[Illustration: Fig. 55.--_Uronychia setigera_.]


Genus ASPIDISCA Ehr. 1830.

(Perty '52; Cl & Lach. '58; Stein '59; Quennerstedt '65, '67, '69;
Mereschowsky '79; Kent '81; Bütschli '88.)

Small, colorless, and rigid forms, with nearly circular to oval
contour. The left side is usually straight, or at least but slightly
convex. The right side is much more convex, and the right margin is
considerably thickened. The ventral side is flat, the dorsal surface
convex, with from one to several longitudinal ridges which run more
or less parallel with the right edge. The peristome is limited to the
left edge, where it forms a small depression which may or may not
reach the anterior border, but which in no case runs around the
anterior margin. The left peristome margin in some cases grows
over the peristome depression toward the right, thus making a sort
of cover for the peristome. In the posterior region is a deep
depression, from which 5 to 12 cirri take their origin. Seven or 8
cirri are placed in the anterior half of the ventral surface and
are arranged more or less in rows. The anus is on the right side in
the region of the anal cirri (Stein). The contractile vacuole is
generally on the right side and similarly located. The macronucleus
is a horseshoe-shaped body. Movement rapid, somewhat in circles, and
rather uniform.

Fresh and salt water.


Aspidisca hexeris Quennerstedt '67.  Fig. 56.

The carapace is elliptical, about 1-1/2 times as long as broad,
rounded at the extremities. The left border of the carapace bears a
spur-like projection. The ventral cirri are short and thick, and are
very characteristic of the species. When moving slowly they look much
like nicely-pointed paint brushes, but when the animal is compressed
they quickly become fibrillated, and then look like extremely old and
worn brushes. These cirri are placed in depressions in the ventral
surface and each one appears to come from a specific shoulder. At the
posterior end an oblique hollow bears 6 unequal cirri placed side
by side. The extreme right cirrus is the largest, and they become
progressively smaller to the opposite end. Dorsal to these lies the
contractile vacuole. The peristome is in the posterior half of the
body and an undulating membrane extends from it into the oesophagus.
The dorsal surface is longitudinally striated by 5 or 6 lines, which
are usually curved. The nucleus is horseshoe-shaped and lies in the
posterior half of the body. Length 68µ; diameter 48µ.


[Illustration: Fig. 56.--_Aspidisca hexeris_.]


This form was incorrectly mentioned as _Mesodinium_ sp. by Peck '95:

In the figure given by Quennerstedt there are only 7 ventral cirri.
In the Woods Hole form there are 8, 7 of which are anterior, 6 of
them about one central one. The eighth cirrus is by itself, near the
base of the largest posterior cirrus. These cirri, in spite of their
size, are easily overlooked and more easily confused, but by using
methylene blue they can be seen and counted.


Aspidisca polystyla Stein.  Fig. 57.

This species is similar to _A. hexeris_, but is smaller, very
transparent, and without the spur-like process on the left edge of
the carapace. The chief difference, however, lies in the number of
anal cirri. These are 10 in number and they are arranged obliquely as
in the preceding species, with the largest one on the right and the
smallest on the left. The ventral cirri are 8 in number, and are
arranged in two rows, one of which, the right, has 4 cirri closely
arranged, the other having 3 cirri close together and one at some
distance, near the largest anal cirrus. The peristome, contractile
vacuole, and nucleus are similar to the preceding. Length 36µ; width
22µ.


[Illustration: Fig. 57.--_Aspidisca polystyla_.]


Stein assigns only 7 ventral cirri to this species, but he also
describes 2 very fine bristle like cilia (p. 125) and pictures them
in figs. 18, 19, 20, and 21 of his Taf. III in the same relative
position as my eighth cirrus. I am positive that cilia do not occur
on the ventral face of this form, and that the characteristic cirri
are the sole locomotor organs.


KEY TO FAMILIES OF PERITRICHIDA.

a. Peristome drawn out into               Family _Spirochonidæ_
   funnel-like process; parasitic

b. Adoral zone and circlet of cilia       Family _Lichnophoridæ_
   at opposite end. Adoral zone           (one genus, *_Lichnophora_)
   left-wound. Parasitic.

c. Adoral zone a left-wound spiral.       Family _Vorticellidæ_
   Attached or unattached forms.

   * Presence at Woods Hole indicated by asterisk.


Genus LICHNOPHORA Claparède '67.

(Gruber '84; Fabre-Domergue '88; Bütschli '88; Wallengren '94;
Stevens 1901.)

Small or medium-sized colorless animals, extremely elastic and
flexible. The anterior part, bearing the adoral zone, is round or
oval in ventral view, and has a flat ventral and a highly arched
dorsal surface. The posterior end of the animal is reduced to a
stalk-like structure which is broadened at the extremity to form
a sucking disk. The surface of this disk and the surface of the
peristome may be brought into the same plane by the characteristic
bending of the stalk portion. A ciliated girdle is placed at the
edge of the sucking disk. A well-developed adoral zone incloses the
peristome; it begins at the mouth on the left side and includes
nearly all of the peristome in its left-wound spiral, the extremity
approaching closely the end near the mouth. The macronucleus is a
long-beaded structure, or it may be in several parts connected by
strands (Gruber). The contractile vacuole is on the left side in the
region of the mouth. Salt water.


Lichnophora macfarlandi Stevens.  Fig. 58.

The body is elongate; oral disk variable in form, attachment disk
clearly defined and constant. The stalk is very contractile and
elastic, constantly changing in shape. When detached from the host
the animal moves with a very irregular and indefinite motion. When
attached it moves freely over the surface on its pedal disk. The
latter is bordered by four membranes composed of cilia. A distinct
axial fiber extends from the pedal disc to the peristome and gives
off a number of branches. This fiber is analogous to the myonemes
in _Vorticella_. An indistinct longitudinal furrow can be made out
occasionally. The nucleus is in 5 or 6 separate pieces, of which 1
is found in the pedal disk and 1 or 2 in the neck.

On the egg capsules of _Crepidula plana_; also reported upon annelids
at Woods Hole.

Length 60µ from disk to extremity of the peristomial disk.


[Illustration: Fig. 58.--_Lichnophora macfarlandi_.]


This form does not agree in all respects with Stevens's species, but
the agreement is so close in other respects that I believe it can be
safely identified as _L. macfarlandi_. The mode of life is different,
and the macronucleus is different, there being from 25 to 30
fragments in Stevens's form and only 5 or 6 in the present one. There
is, however, the same evidence of chain formation in both of them.
The length of the oral cilia in  Stevens's form is 18µ in fixed and
30µ in living forms. In the Woods Hole form the cilia are not more
than half that length.


KEY TO THE MARINE GENERA OF VORTICELLIDÆ.

Diagnostic characters: Attached or unattached forma of peritrichous
ciliates in which the adoral zone seen from above forms a right-wound
spiral. A secondary circlet of cilia around the posterior end may be
present either permanently or periodically.

1. Posterior ciliated girdle              3
   permanent around an attaching disk

2. Posterior ciliated girdle,             4
   temporary during motile stage

3. Body cylindrical:

  (a) With ring of stiff bristles         Genus _Cyclochæta_
      above the ciliated girdle

  (b) Without accessory ring of           Genus _Trichodina_
      bristles; with velum

         Body conical; general            Genus _Trichodinopsis_
         surface ciliated

4. No test and no stalk                   Genus _Scyphidia_

5. No test; with stalk containing         8
   contractile thread

6. No test; with stalk but without        Genus _Epistylis_
   contractile thread

7. With a test; with or without           Genus *_Cothurnia_
   a stalk

8. Individuals solitary                   Genus *_Vorticella_

   Individuals colonial;                  Genus *_Zoothamnium_
   entire colony contractile

   Individuals colonial; parts            Genus _Carchesium_
   only of the colony contractile

   * Presence at Woods Hole indicated by asterisk.


Genus VORTICELLA (Linnæus 1767) Ehr. '38

(Bell Animalcule Leeuwenhoek 1675; Ehrenberg '38; Dujardin '41; Stein
'51; Cl. & Lach. '58; Greeff '70; Bütschli '88; Kent '81; Stokes '88;
etc.)

Medium-sized ciliates of general bell-like form. They may be
colorless, or yellow and green through the presence of Zoochlorella.
When not contracted, the peristome end is widespread, rarely
narrowed. The adoral zone and peristome agree with the details given
in the family characteristics. The chief character is the attachment
of the posterior end by means of a single, longer or shorter, stalk,
which contains a highly contractile thread easily distinguished
in the living animal. Another character is the absence of colony
formation. Contractile vacuole, single or double, usually connected
with a sac-like reservoir. The macronucleus is invariably long and
band-formed, with attached micronucleus. Fresh and salt water.

So many species of _Vorticella_ have been described that the task of
collecting data and of arranging the synonyms is extremely irksome
and difficult. Stokes enumerates 66 species, inhabiting fresh and
salt water, and several other new species have been added since his
work. I am impressed with the fact that new species have been created
without proper regard for the manifold variations which nearly all
of the _Ciliata_ show, and I believe the 66 species might be safely
reduced to 12 or 15.


Vorticella patellina Müller.  Fig. 59.

Body campanulate, widest at anterior border, from which it tapers
directly to the pedicle. The diameter of the peristome is a little
larger than the length of the body. The ciliary disk is but little
elevated. The cuticle is not striated and the body plasm is quite
transparent. Length 52µ.


[Illustration: Fig. 59.--_Vorticella patellina_.]


Vorticella marina Greeff.  Fig. 60.

The body is conical but variable, and may he short or elongate, so
that relative length and breadth offer no chance of identification.
In general the body is campanulate. The distinguishing feature is the
transverse annulation of the bell.

Small, but common, and grows in small social groups. Length 35µ.


[Illustration: Fig. 60.--_Vorticella marina_.]


Genus ZOOTHAMNIUM (Bory de St. Vincent 1824) Stein '38, '54.

Colorless and highly contractile forms growing in small or large
colonies. The form and structure of the individuals is not different
from _Vorticella_. The colonies are usually richly branched upon
the dichotomous plan and the entire colony is contractile. The main
character is that with each division of the individual the stalk
also divides, each daughter cell getting one-half of the parent stem.
The stems therefore remain in communication, so that a simultaneous
contraction results, and the colony as a whole is withdrawn. In some
species so-called macrogonidia, or larger sexual individuals, are
developed alongside the usual ones. Fresh and salt water.


Zoothamnium elegans D'Udekem '64?  Fig. 61.

The bodies are variable--peristomial border widely dilated, tapering
and attenuate posteriorly. The pedicle is slender, smooth, and
transparent, and branches sparsely at its distal extremity. There
are but few zooids (3 to 4). The ciliary disk projects conspicuously
beyond the peristomial border. The pharyngeal cleft is very distinct
and extends beyond center of body. Length of body 80µ.


[Illustration: Fig. 61.--_Zoothamnium elegans_.]


Genus COTHURNIA (Ehr. '31) Clap. & Lach. '58.

Colorless forms of medium size-in some cases they may be green
by Zoochlorella. The general structure is similar to that of
_Vorticella_, but the individuals are elongate and occupy houses. The
macronucleus is invariably long and band-form. The distinguishing
character is the colorless or brownish lorica of quite variable form
but always attached. These houses may be finger-formed, with widened
center, or widened mouth, or constricted mouth, and the like.
Ring-formed swellings are frequently developed. Sometimes the mouth
becomes twisted and the lorica is therefore bilateral. The houses
are attached either directly to some foreign object or by means of
a short stalk. The animals are similarly fastened to the lorica,
sometimes directly, sometimes by means of a short stalk. When they
contract they draw back to the bottom of the lorica; when expanded
they usually stretch out of the mouth opening. In some forms there
is an operculum, by means of which the opening of the shell can be
closed when the animal is retracted. Fresh and salt water.

The number of species of _Cothurnia_ has become so great that the
difficulty in placing forms is almost sufficient to discourage the
systematist; as Bütschli well remarks, the variations in the theca
have been made the basis of new species so many times that the
genus is almost as confused as _Difflugia_ among the rhizopods or
_Campanularia_ among the hydroids. The length of cup, of stalk,
the presence of annulations on stalk or cup, etc., have given rise
to many specific names, the majority of which I believe can be
discarded. According to such differentials the same branch of an alga
holding a hundred specimens of _Cothurnia crystallina_ yield 10 or 12
species, whereas they are merely growth stages of one and the same
form.


Cothurnia crystallina Ehr.  Fig. 62.

Synonyms: _Vaginicolla crystallina_ Ehr., Perty, Eichwald; _V.
grandis_ Perty; _V. pedunculata_ Eichwald; _Cothurnia crystallina_
Claparède & Lachmann, D'Udek.; _C. gigantea_ D'Udek; _C. maritima_,
_C. crystallina_ Cohn; _C. grandis_ Meresch.

The form of the cup shows the greatest differences; sometimes it is
cylindrical, sometimes elongate thimble-shape, sometimes pouch-shape,
corrugated or smooth on the sides, and wavy or smooth on border.
Frequently the basal part becomes stalk-like, but this is very short.
When present, the stalk may or may not have a knob-like swelling. The
animal within the cup may or may not be borne on a stalk, and this
stalk may or may not be knobbed. The cups are colorless or brown. The
animal is very contractile and may stretch half its length out of the
cup or retract well into it. There is no operculum. The length of the
cup varies from 70µ to 200µ (_C. gigantea_; _Vag. grandis_, etc.).
From Entz.

There is nothing to add to Entz's characterization of this species,
which is found both in fresh and salt water. The variability of the
cup and stalk is quite noticeable in the Woods Hole forms.


[Illustration: Fig. 62.--_Cothurnia crystallina_.]


Cothurnia imberbis Ehrenberg, var. curvula Entz.  Fig. 63.

Synonyms: _C. imberbis_ Kent et al.; _C. curvula_ Entz; _C. socialis_
Gruber?

The lorica is swollen posteriorly, narrowest at the oral margin, bent
on its axis and is supported on a short stalk. It is perfectly smooth
and without annulations. The animal itself has no definite stalk.
When fully expanded the animal emerges but slightly from the margin
of the cup. Fresh and salt water. On red algæ. Dimensions of Woods
Hole form: Cup 50 to 55µ long; greatest diameter 22µ; length of stalk
4 to 5µ.


[Illustration: Fig. 63.--_Cothurnia imberbis_.]


Cothurnia nodosa Claparède & Lachmann.  Fig.64.

   A. Smooth cup.--_Cothurnia maritima_ Ehr., Eichwald, Stein, Kent.

   B. Cross-ringed cup.--_C. pupa_ Eichwald, Stein, Cohn; _C. nodosa_
      Cl & L.; _V. crystallina_ Entz '78; _C. pontica_ Meresch.,
      Kent; _C. cohnii_ and _pupa_ Kent; _C. longipes_ Kellicott '94.

The cup is elongated, swollen centrally, tapering at oral end
and conical at base or rounded. Oral opening either circular or
elliptical. Cross rings may or may not be present, and the cup is
either smooth or annulate. Length of cup 70µ to 80µ. The stalk which
supports the cup is extremely variable in length. The animal is borne
upon a stalk of variable length within the cup.

Entz states that the many variations which this species exhibits run
into each other so gradually that he does not believe it wise to
separate them. The Woods Hole forms which I found on algæ of various
kinds were nearly of a size, and did not vary much from the one
figured. Kellicott '94 described a _Cothurnia_ from Woods Hole under
the name of _C. longipes_, which I believe is only a long-stemmed
variety of _C. nodosa_. My form has the following dimensions: Cup
75µ; cup stalk 38µ; animal stalk 14µ.


[Illustration: Fig. 64.--_Cothurnia nodosa_.]


KEY TO FAMILIES OF SUCTORIA.

a. Unattached forms; ventral cilia        _Hypocomidæ_
   present; one suctorial tentacle

b. Attached forms; thecate and            _Urnulidæ_
   athecate tentacles simple,
   one or two in number

c. Thecate; posterior end of cup          _Metacinetidæ_
   drawn out into stalk; walls
   perforated for exit of tentacles

d. Stalked or unstalked; globular;        _Podophryidæ_
   tentacles of different kinds, some     (2 genera *_Ephelota_,
   knobbed, others pointed                *_Podophrya_)

e. Naked or thecate; stalked or not;      _Acinetidæ_
   tentacles numerous, usually
   knobbed and all alike

f. Naked; athecate; tentacles             _Dendrosomidæ_
   numerous, all alike, knobbed and
   grouped in tufts. They may be
   simple or branched.

g. Sessile forms resting on basal         _Dendrocometidæ_
   surface or on a portion raised
   like a stalk; tentacles many;
   short and knobbed; distributed
   on apical surface or localized
   on branched arms

h. Stalked or sessile; tentacles          _Ophryodendridæ_
   long, rarely knobbed, supported
   on proboscis-like processes

   * Presence at Woods Hole indicated by asterisk.


Genus PODOPHRYA Ehr. '33.

(Bütschli '88; Stein '59; Perty '52; Cienkowsky '55; Quenn. '69;
Hertwig '77; Maupas '81.)

The body is globular, with tentacles radiating in all directions. The
tentacles may be very short or very long. The stalk also is either
short or long, and some species form stalks but rarely (_P. libera_).
The macronucleus is centrally placed and globular to ovoid in form.
The contractile vacuole is usually single. Reproduction takes
place by division; the distal half developing cilia and becoming a
swarm-spore. Fresh and salt water.


Podophrya gracilis, n. sp.  Fig. 65.

Of all the _Podophrya_ that have been described not one approaches
this minute form in the relative length of the stalk. The body is
spherical and is covered with short capitate tentacles. The stalk is
extremely slender, bent, and without obvious structure. There are
one or two contractile vacuoles in the distal half of the body. The
nucleus is small and is situated near the insertion-point of the
stalk. Reproduction not observed. Diameter of body 8µ; length of
stalk 40µ. Only one specimen seen.


[Illustration: Fig. 65.--_Podophrya gracilis_.]


Genus EPHELOTA Str. Wright '78.

(Bütschli '88; Ishikawa '96; Sand '98.)

Small to medium-sized and large forms; colorless to brown. The body
is globular or oval or wedge-shape, sometimes quadrangular. The stalk
is variable, sometimes 1 mm. in length. The diameter of the stalk
increases from the point of attachment to the body of the animal;
it is usually striated either longitudinally or transversely, or
both. The tentacles are of two kinds and are usually confined to
the anterior half of the body. Some are long and sharp-pointed
and adapted for piercing; others are short, cylindrical, usually
retracted and capitate, adapted for sucking. Contractile vacuoles
vary from one to many. The macronucleus is nearly central in position
and usually of horseshoe shape, but is frequently branched and
irregular. Reproduction is accomplished by external multiple budding,
usually from the anterior half of the body. Salt water.


Ephelota coronata Str. Wright.  Fig. 66.

Synonyms: _Hemiophrya gemmipara_ S. K.; _Podophrya gemmipara_
Hertwig.

The body is spheroidal, ovate, or pyriform, with numerous
sharp-pointed tentacles and a few straight, uniform tentacles. The
stalk is about three times the length of the body and tapers from its
widest part at the insertion in the body to the narrowest part at the
point of attachment. It may or may not be longitudinally striated.
This is one of the commonest of the _Suctoria_ found at Woods Hole.
It is usually present on Campanularian hydroids, but may be found on
algæ and Bryozoa.

Length of body 90µ to 200µ.


[Illustration: Fig. 66.--_Ephelota coronata_.]


Genus ACINETA Ehr. '33, Bütschli '88.

(Stein '54, '59; Claparède & Lachman '58; Quennerstedt '67; Hertwig
'76; Mereschowsky '79; Entz '84; Kent '81; Maupas '83; Gruber '84;
Gourret & Roeser '86, and others.)

Small to medium-sized forms. The distinguishing feature is that the
stalk is swollen at the distal extremity to form a cup or basin in
which the animal rests. The cup may be developed until the body is
nearly inclosed. The macronucleus is spherical or band form. The
contractile vacuole is usually single. Budding, so far as known, is
endogenous. Fresh and salt water.


Acineta divisa Fraipont '79.  Fig. 67.

This extremely graceful form is common on Bryozoa at Woods Hole. The
cup is shaped like a wine glass and is specifically characterized by
a cup-formed membrane upon which the animal rests. The animal thus
has the appearance of being suspended on the edge of the cup. The
stalk is slender and about 4 times the length of the body. The
tentacles are all capitate and distributed, and about 2-1/2 times the
body length. They sway back and forth very slowly. The nucleus is
spherical and central in position. The contractile vacuole lies near
the periphery.

Length of body 27µ; of stalk 100µ; of extended tentacle 65µ.


[Illustration: Fig. 67.--_Acineta divisa_.]


Acineta tuberosa Ehr.  Fig. 68.

Large forms of _Suctoria_ with tentacles arranged in fascicles. The
stalk is variable in length and the cup is frequently so delicate
that it can barely be made out. A specific characteristic is the
break in continuity of the cup at different points, and through these
places the tentacles emerge in bundles. The tentacles are capitate
and in the Woods Hole form, 15 in number in each of the two bundles.
The endoplasm is granular and yellowish in color. The coloring matter
is frequently arranged in patterns. The nucleus is spheroidal. The
contractile vacuole is in the anterior third of the body about midway
between the bundles of tentacles. Reproduction not observed.

Length of body 330µ.


[Illustration: Fig. 68.--_Acineta tuberosa_.]


Genus TRICHOPHRYA Clap. & Lach. '58.

(See Kent '81; Entz '84; Bütschli '88; Sand 1901.)

Small forms to medium size; no cups or stalks. The body is spherical
to elongate, usually, however, more or less irregularly lobed and
changeable. The tentacles are in fascicles which are usually borne
upon lobed or swollen places. The body is always more or less spread
out. Contractile vacuoles variable. The macronucleus is spherical,
elongate, band-formed or horseshoe-shaped. Reproduction takes place
by endogenous budding, and the swarm spores are flat or lenticular
with a distinct ciliary girdle. They are frequently parasitic. Fresh
and salt water.


Trichophrya salparum Entz '84.  Fig. 69.

Bütschli '88; Schewiakoff '93; _Trichophrya ascidiarum_ Lachmann '59;
René Sand 1901.

The body is somewhat cup-form, with a large, flat base. The anterior
border is rounded, each of the ends being somewhat truncate and
carrying a bundle of tentacles all capitate and similar. These may be
continued internally as far as the nucleus (Sand). The cytoplasm is
uncolored, but may contain some brilliant granules. The nucleus is
granular, and spherical, band or horseshoe formed.


[Illustration: Fig. 69.--_Trichophrya salparum_.]


This species was found by Dr. G. Hunter on the branchial bars of the
Ascidian _Molgula manhattensis_, where great numbers of them are
often parasitic.




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