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                                  THE
                                NAUTILUS
                              A QUARTERLY
                        DEVOTED TO THE INTERESTS
                            OF CONCHOLOGISTS


                         EDITORS AND PUBLISHERS:

  H. A. PILSBRY, Special Curator of the Department of Mollusca, Academy
                   of Natural Sciences, Philadelphia.

    C. W. JOHNSON, Curator of the Boston Society of Natural History.
 ═══════════════════════════════════════════════════════════════════════
 Vol. XXXI.                  OCTOBER, 1917.                        No. 2
 ═══════════════════════════════════════════════════════════════════════




                               CONTENTS:


 Notes on the variation of Ischnochiton conspicuus. By _E. P. Chace_  37

 Lampsilis ventricosa cohongoronta in the Potomac River. By _Wm. A.
 Marshall_                                                            40

 Collecting about Guantanamo Bay, Cuba. By _John B. Henderson_        41

 Amnicolidæ from Oneida Lake, N. Y. By _H. A. Pilsbry_                44

 New Genera and Species of Central American Naiades. By _L. S.
 Frierson_                                                            47

 On the rate of growth of pond Unios. By _L. S. Frierson_             49

 A new South African Nesopupa. By _H. A. Pilsbry_                     50

 A new Gundlachia from Guatemala. By _Bryant Walker_                  51

 A list of shells from the East Coast of Florida. By _Bryant Walker_  53

 Collecting in Digby, Nova Scotia. By _Lilian Dyer Thompson_          57

 A new type of the naiad-genus Fusconaia. By _A. E. Ortmann_          58

 The Relation of snail fauna to floods. By _A. Richards_              64

 William Bullock Clark                                                68

 Publications received                                                69

 Notes                                                                71
 ═══════════════════════════════════════════════════════════════════════

                    C. W. JOHNSON, Business Manager,
                   Boston Society of Natural History,
                            Berkeley Street,
                             Boston, Mass.


       Entered as Second-Class matter at the Boston Post-Office.




                   The Cruise of the “Tomas Barrera”


                          By JOHN B. HENDERSON

 32 full-page illustrations in black and white. 5 color plates. 5 maps.
                           Octavo. $2.50 net.

This is the narrative of a scientific expedition to Western Cuba and the
Colorados Reefs, with observations on the Geology, Fauna, and Flora of
the region, undertaken in May and June, 1914, under the joint auspices
of the Smithsonian Institution and the Cuban Government.

  “A genuine feast for the reader. It is a narrative replete with
  interest concerning the roads, mountains, trees, dwellings, the
  inland lakes and ponds (alive with queer fish), many species of
  mollusca, found along the coast; the land crabs and their curious
  habits,” etc.—_Louisville Courier Journal._

                            ALL BOOKSELLERS

          NEW YORK        =G. P. PUTNAM’S SONS=         LONDON
          2 West 45th St.                       24 Bedford St.




                         NEW SHELL LISTS FREE.


A new list of Philippine Land Shells covering many of the most beautiful
forms at greatly reduced prices. A list of 2,000 species of shells,
priced at 5 to 10 cents per species. Two lists of the finer cabinet
shells, the more aristocratic forms. List of American Land Shells.
Illustrated list of Philippine Shells. Further lists in preparation. I
desire correspondence with collectors who wish to build up large and
extensive cabinets. I have in stock over three times as many species as
are covered by my lists. Collections of a strictly scientific nature
purchased for cash.

                            WALTER F. WEBB,

                         202 Westminster Road,

                            ROCHESTER, N. Y.

                  *       *       *       *       *

 Exchange notices not exceeding three lines will be free to subscribers
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                  *       *       *       *       *

FOR EXCHANGE: Marine shells from various parts of the world, for others.
Send lists.

J. R. LEB. TOMLIN, 120 Hamilton Road, Reading, England.

[Illustration:

  WASHINGTON MEETING, 1914

  Bryant Walker
  Geo. H. Clapp
  T. H. Aldrich
  John B. Henderson
  H. A. Pilsbry
  Wm. H. Dall
  Paul Bartsch
]




                             THE NAUTILUS.


 ═══════════════════════════════════════════════════════════════════════
 VOL. XXXI.                  OCTOBER, 1917.                        NO. 2
 ═══════════════════════════════════════════════════════════════════════




         NOTES ON THE VARIATION OF ISCHNOCHITON CONSPICUUS CPR.


BY E. P. CHACE.

To the naturalist the study of variation and environment and their
relation to each other is always interesting and to the conchologist who
studies his shells in their natural surroundings as well as in the
cabinet many things are revealed. It is not, often, however, that
variation in form may be so easily traced to qualities of environment as
in the following instance.

_Ischnochiton conspicuus_, Cpr. is common at San Pedro and is usually
found on the under side of rocks in sandy tidepools. In this situation
they grow quite regularly, showing but slight variation in form. They
are active fellows and evidently sensitive to light; for if the rocks to
which they are clinging are turned over, they soon glide away, always
taking the shortest route to the under side of the rock.

While cleaning a lot of this species taken at San Pedro last fall two
specimens were noticed which differed so widely from the others that
they might easily have been mistaken for another species. They were much
wider and lower-arched than the typical form and the posterior corners
of the valves were rounded off, making the lateral areas very narrow.

Hoping to find more specimens of this odd form, a trip to Point Firmen
was devoted wholly to the collection of chitons, with interesting
results. The usual species were found in the tidepools including
numerous specimens of _Ischnochiton conspicuus_ of the ordinary form.
Ledges of soft rock beyond the tidepools contained many old pholad holes
and in these were found the form for which I was searching. Twenty
specimens of various sizes were collected from as many pholad holes. In
the larger specimens the foot had become so greatly enlarged to fit the
concave bottoms of the holes that it was impossible for them to curl up
in the usual manner. Some of these specimens were so badly eroded by the
sand and gravel which wash in and out of the holes that the anterior
valve was reduced to two thirds of its normal height.

In color pattern, sculpture, and mantle characters these specimens were
identical with those from the tidepools, and, as will be seen by
referring to the table of measurements, the smaller specimens approach
quite closely to the proportions of the typical or tidepool forms.

     TYPICAL OR TIDEPOOL FORMS.     ║   SPECIMENS FROM PHOLAD HOLES.
               (Lot 1)              ║              (Lot 2)

  _Lon._   _Lat._  _Index._  _Div._ ║ _Lon._   _Lat._  _Index._  _Div._
       99       35     2.52     130°║      65       33     1.97     135°
       83       33     2.51     130°║      63       32     1.97     155°
       83       30     2.76     125°║      62       27     2.29     140°
       62       22     2.80     125°║      60       30     2.00     130°
       59       23     2.56     130°║      56       29     1.93     130°
       38       14     2.71     130°║      42       17     2.47     130°

In brief, Lot 1 shows an angle of divergence constant at 125° to 130°,
where Lot 2 shows an angle varying from 130° to 155°, and a proportion
of length to width 2.51 to 2.80 as against a proportion ranging from
2.47 to 1.93.

The noticeable differences to the eye are first, the narrow and sharply
raised lateral areas, and second, the shape of the posterior edge of the
median valves. In the tidepool specimens the posterior or exposed edge
of each valve is a straight line, while in specimens from the pholad
holes this line becomes a double convex curve, the most posterior
portion of the valves being about midway between the beaks and the
girdle.

These differences seem to be explained by the following facts. In
collecting, the tidepool specimens are usually found on the under side
of large rocks and well back from the edge. This situs protects them
from the light which they evidently find objectionable, but it makes
necessary a nightly journey of about two feet to the nearest growth of
algae on which they feed. This activity stretches the girdle downward
from the edges of the valves and permits a free play of all the valves
so that the mantle deposits its shelly secretions according to the
normal habit of the species. The specimens living in the pholad holes,
however, apparently never leave them as they are frequently found
feeding on the fucus which overhangs them. It protects them from the
light, so they have no occasion to move about, and the sand which is
washed down into these burrows would make re-entrance almost impossible.
A series of these specimens shows a gradual change of form. The young
specimens are very similar to young specimens from the tidepools, but as
they increase in size they become crowded so that the valves press
against each other, especially at the posterior end where the valves are
bent back across the bottom of the hole. This crowding of the valves
upon each other and the crowding of the girdle against the outer edges
of the valves so displaces portions of the mantle as to cause the
changes noted above.

Several specimens from each situs were disjointed and a study of the
individual valves showed that those from pholad-hole specimens were
thicker and had shorter sutural plates and a wider sinus, this last
being especially noticeable in the valves from the posterior end.
Apparently this change in the sinus is the result of the broadening of
the connecting ligaments due to compression by the crowding valves.

A count of the insertion plates of these disjointed specimens was made
and considerable variation noticed. So much, in fact, that more
specimens were pulled apart for the express purpose of counting these
plates. Representative counts were as follows: 9 slits on the anterior
valve, 2‒3 on the median valves, and 10 on the posterior. Others show
12, 2‒3, 8; 11, 2‒3; 14, 3‒4, 11. Absolutely no difference in this
character could be found between specimens from the tidepools and those
from the pholad holes.

On page 64 of vol. xiv of the Manual of Conchology, Dr. Pilsbry says,
“Carpenter has given a varietal name to a broad, worn specimen which he
thus describes:

“Var. _solidus_. Very solid, wide, ashen; inside whitish, the posterior
valve with 10, central valve 2‒3, anterior valve 12 slits. Length 72,
breadth 40, divergence 130°. Carpenteria, near Sta. Barbara, Cal. This
is scarcely more than an individual variation. The mantle (girdle) is
normal. The sculpture is worn away except at the edge. It has evidently
lived in a very exposed situation.”

From this description and the figure which he gives of the valves it
would seem that this is the same form as my specimens from the pholad
holes. I fully agree with Dr. Pilsbry that it is hardly worthy of
varietal rank. It is, however, too distinct in appearance to be labeled
simply _Ischnochiton conspicuus_, Cpr., and I have therefore marked
these specimens from the pholad holes _I. conspicuus_, Cpr., _form
solida_, Cpr., using the term _form_ as advocated by Dr. Cockerell, “to
designate variations plainly due to environment.”[1]




        LAMPSILIS VENTRICOSA COHONGORONTA IN THE POTOMAC RIVER.


BY WILLIAM A. MARSHALL.

In 1912 Dr. A. E. Ortmann recorded[2] finding in the Potomac River a
variety of _Lampsilis ventricosa_[3] to which he gave the name
_cohongoronta_. His records were:

  September 4, 1909. Potomac River, Hancock, Washington, Co., Md. (about
    two dozen).

  May 9, 1911. South Branch, Potomac River, Southbranch, Hampshire Co.,
    W. Va. (about a dozen).

  August 16, 1911. Shenandoah River, Harper’s Ferry, Jefferson Co., W.
    Va. (a single male, below medium size).

  May 6, 1912. South Branch, Potomac River, Romney, Hampshire Co., W.
    Va. (about a dozen).

Dr. Ortmann remarked “It is probable that this species will turn up
elsewhere in the Potomac. The localities known at present are all to the
west of the Blue Ridge Mountain, that is to say, within the Great
Alleghany Valley and the Alleghany Mountains.”

Perhaps the above prediction has been realized in a specimen found at
Great Falls, Md., by Mr. Manly D. Barber of Knoxville, Tennessee, in
Sept. 1915. At that time Mr. Barber brought to the National Museum a
basketful of naiades which he had collected the same day at Great Falls,
about 18 miles above Washington. Among the shells, which were mostly
dead ones, was a specimen of _cohongoronta_, dead, but in a fine state
of preservation and with the periostracum nearly unblemished except for
the usual erosion at the beaks. Its appearance indicated that it had
been recently alive and that its home had been in the immediate vicinity
of the place in which it was found. Had it been washed down from
Harper’s Ferry, some 50 or more miles above Great Falls it probably
would have shown ill effects from so long a journey.

When found the two valves were separated, but so accurately do they fit
together that it is evident they belong to the same individual. The fact
that the valves were separated and yet were found near each other is
additional (though not conclusive) evidence that they had not been
transported any great distance by currents. At any rate this is the
first recorded finding of the species in the Potomac River so far south
as Great Falls.

The specimen is rather a small one. It measures, length 71 mm.; height
47 mm.; diameter 28 mm. It is in the collection of the U. S. National
Museum, catalogue number 273834.




     COLLECTING DAYS ABOUT THE NAVAL STATION, GUANTANAMO BAY, CUBA.


BY JOHN B. HENDERSON.

In March last, while waiting for a boat to take us to Haiti, Dr. Bartsch
and I spent nearly three weeks at the U. S. Naval Station at the
entrance to Guantanamo Bay. We employed our time in exploring the
country about and subjecting it to a high degree of intensive
collecting. In this eastern corner of Cuba the coastal strip of some ten
miles in width is a semi-arid region with a complex of mountains that
are either quite bare of trees or, at most, covered with a scrub forest
and low-growing spiny shrubs, with, here and there, a wealth of cacti
that almost suggests Lower California. The rock foundation of all this
region,—barring some shore strips of very recently elevated coral, is
everywhere composed of about everything in the line of rocks except
limestone. This is a condition that in the Antilles usually spells
disappointment and failure to the snail hunter. North of the big bay and
then across several miles of low flat country, just where the foothills
of the sierras begin, lies the city of Guantanamo, interesting to us as
the home of Charles Ramsden, the naturalist. Just north of Guantanamo is
a great rampart of high limestone mountains which beckon most alluringly
to the collector. Sections of this rampart, somewhat arbitrarily marked
off, are the “Monte Verde,” the “Monte Toro” and the “Monte Libano” of
classic fame in Cuban Natural History.

In company with Ramsden we spent a wonderful day on nearby Monte Libano
but a revolution that was then devastating the province and filling the
land with incendiaries and bandits drove us out of this richer field and
obliged us to confine our attentions thereafter to the arid country
lying within the safer limits of the Naval Station,—some fifty square
miles upon which Uncle Sam holds a long lease.

It seems to be a natural law that arid or desert lands support but few
species of snails, but that these few species exist in great numbers and
that they take on a very considerable range of variation. All this is
perfectly true of this region. We were constantly amazed by the great
number of specimens to be found; and each day of exploration in some new
valley or over some range of hills added even greater figures of
abundance to our already astonishing records.

The “prevailing” snail of this region is _Cepolis ovumreguli_ Lea. Its
shell is very suggestive of the true helix of Spain or Algeria of the
_lactea_ group. The variation is exceedingly great in color, size and
shape, and it would make a dozen excellent species if the intermediates
were left out of account. Those living near the coast and among the
cacti of the most arid parts of the district are of whiter and more dull
color, are more banded and show a decided tendency to abnormalities,
especially about the apertures. Specimens from further inland are more
polished and shining, even as though varnished, and are much more given
to a dotted or fly-specked type of ornamentation than to bands. A
fence-post or a dead tree-limb with a hundred specimens closely
assembled in aestivation was no unusual sight. We learned finally to pay
no attention to them. Upon the low bushes in certain localities the
lovely little _Cepolis lucipeta_ Poey cling like berries. These are the
largest and finest of the species I have ever seen. The range of color
variation in this delightful little snail is also very great, but the
colors never blaze out in the vivid flash of the Polymitas. The blues
and purples and chestnut browns are subdued but very rich and splendid.
One very noticeable color form is the subsp. _velasqueziana_ of Poey
where the many broken bands of the type coalesce into two broad
bluish-black zones of solid color.

As nearly all the vegetation of this dry region bears thorns we did not
at first discover that many of these thorns were in reality Macrocerami.
When we did find this out we could see nothing else. Bartsch and I
finally agreed, and shook hands upon it, that we would gather no more of
them, and a stiff penalty was placed upon any violation of the compact.
Two hundred and more from one bush is an earlier record before we really
got started. This is the _Macroceramus festus_ (Gundl.) Pfr., blue and
yellow and buff in color. Another arboreal snail of this section is
_Polymita versicolor_ Born and it is probably very abundant in places
although we never saw more than fifteen or twenty on any one tree. This
is to me the least attractive species of that wonderful genus of richly
painted snails. The brilliant yellow and pink are too primitive and the
two colors do not seem to harmonize very well. It always impresses me as
an experimental species that was laid aside in nature’s laboratory as
not wholly a success.

There were some ground snails too, but to secure living ones required
much grubbing up of tufts of tall grass and shaking out their roots,
like digging up miniature potatoes. These are the _Annularia putris_
(Gundl.) Pfr. and the _Chondropoma marginalbum_ (Gundl.) Pfr., the
latter apparently quite rare. There are no minute things beyond some few
_Thysanophora inaguensis_ Weinland.

Some days we spent gathering marines on the little pebbly beaches hidden
far down under the lofty cliffs that mark this rugged shore line, and we
obtained some unusual species washed up from the exceedingly narrow
island-shelf; blue water is but a few hundred yards out. Among these are
some _Conus cedonulli_ Lam. Beach collecting is, however, an
aggravation; and too much of it becomes a misdemeanor in the collector’s
ethical code, for it obliges an acceptance of something short of the
best.




                   AMNICOLIDÆ FROM ONEIDA LAKE, N. Y.


BY HENRY A. PILSBRY.

The New York College of Forestry, under the direction of Professor Hugh
P. Baker, is carrying on a biological survey of Oneida Lake and has
issued an interesting bulletin[4] upon the relations of mollusks to
fish, by Frank C. Baker. Some _Amnicolidæ_ obtained during this work,
and subsequent to the preparation of the bulletin were submitted to the
writer. The collection proves to be of considerable interest, including
some species not before noticed.


AMNICOLA BAKERIANA, n. sp.

The shell is umbilicate, turrited-conic, thin, whitish-corneous,
somewhat translucent, with unevenly developed striation, distinct, and
close in places, weaker and sparse elsewhere. The summit is decidedly
obtuse, as in _A. limosa_, the first whorl being nearly planorboid;
subsequent whorls are evenly, strongly convex. The aperture is very
shortly ovate, almost round, its length contained almost 2½ times in
that of the shell. Peristome thin, in contrast with the preceding whorl
for a short distance.

Length 4.3, diam. 2.7 mm.; 5 whorls (type).

Length 3.75, diam. 2.3, length of aperture 1.35 mm.; 4⅔ whorls.

Length 4.1, diam. 2.75, length of aperture 1.65 mm.; 4⅔ whorls.

Oneida Lake; off Short Point in 8½ ft., mud bottom. Lower South Bay, in
18 ft., on mud bottom.

This species resembles _A. limosa_ in the conspicuously obtuse apex, but
differs by the more elevated, turrited spire and the smaller calibre of
the whorls, hence smaller aperture. It is also a weaker shell, with more
whorls in specimens of the same length.

There is also an abundant smaller form, resembling the typical form in
texture, apex and shape of the whorls, varying in form, but relatively
broader than the type. There are some intermediate examples, but as Mr.
Baker considers it desirable to have a designation for this form, it may
be called _A. bakeriana_ form _nimia_. The type measures: length 3,
diam. 2.5, length of aperture 1.4 mm.; 4 whorls.


AMNICOLA CLARKEI, n. sp.

The shell is narrowly umbilicate, conic, a little obtuse at the apex,
corneous, nearly smooth. The whorls are very convex, separated by a deep
suture, the last whorl tubular. The aperture is distinctly oblique,
almost circular, the upper end rounded, but a trifle more narrowly so
than the base. It projects but little beyond the preceding whorl
laterally. The peristome is thin, continuous, scarcely or barely in
contact with the preceding whorl above.

Length 3.1, diam. 1.9, length aperture 1.1 mm.; 5 whorls (type).

Length 2.8, diam. 1.6, length aperture 0.85 mm.

Operculum having the spiral rather large, the nucleus being above the
lower third.

This little species resembles _Lyogyrus_ by its tubular whorls of small
calibre. The whorls are more convex and increase less rapidly than in
_Amnicola walkeriana_, which is also less slender. _A. schrockingeri_
Ffld. has less deeply convex whorls, and the apex is more acute. _A.
bakeriana_ is much larger, with a more obtuse apex.

Found in Short Point Bay, Oneida Lake, near shore, in 3 feet of water,
bottom of sand with algae; also in Lower South Bay, etc. Collected by
Mr. F. C. Baker.

It is named for Dr. John M. Clarke, the distinguished Director of the
Museum of the State of New York.


AMNICOLA ONEIDA, n. sp.

The shell is typically more slender than _A. lustrica_, turrited-conic,
narrowly umbilicate, corneous, minutely striate. The apex is slightly
obtuse, but the first whorl projects visibly, as in _lustrica_, whorls
_very convex_, parted by a _deep suture_. The aperture is ovate, small,
its length contained more than 3 times in that of the shell; upper
extremity narrowly rounded. The peristome is continuous, thin, very
briefly in contact with the preceding whorl above.

Length 4, diam. 2, length of aperture 1.25 mm.; 6 whorls.

Lower South Bay, Oneida Lake, N. Y., collected by F. C. Baker, 1916.

This species is typically narrower than _A. lustrica_ Pils., with a
smaller aperture and shorter whorls; but it is chiefly distinguished by
the more convex whorls (deeper suture), and the rounded instead of
angular posterior end of the aperture. In _Paludestrina nickliniana_ the
last whorl is much longer. Possibly it may be a subspecies of
_lustrica_, yet it has so distinct an appearance that a special name
seems desirable. There are also wider examples, which still differ from
_lustrica_ by the deeper suture and aperture.




          NEW GENERA AND SPECIES OF CENTRAL AMERICAN NAIADES.


BY L. S. FRIERSON.

In 1893 Messrs Crosse and Fischer divided the Mexican Naiades into quite
a number of sections, to which they assigned names. Almost
simultaneously (in 1900) von Martens and C. T. Simpson, in treating the
Central American Naiades, accepted some of these sections of Crosse and
Fischer, raising them to generic or subgeneric rank. Because of paucity
of material, considerable diversity of opinion concerning the specific
identity of several species may be noted in the works of these authors.
Furthermore, their work of classification being done independently and
from different points of view, the same species was sometimes placed by
them in different genera.

Thanks to the arduous labors of A. A. Hinkley, who has again and again
enriched our cabinets with material and data from these tropical
countries, we are enabled to offer the following suggestions concerning
some of the genera of these shells, and also the description of an
unpublished species.

NEPHRONAIAS. This genus has for its type the _Unio plicatulus_, Küster,
a species identified by von Martens as belonging to the Lampsiline
shells, as _aztecorum_. Mr. Simpson however believed it to be nearly
allied to the _persulcatus_, a markedly Unioid shell. In this the writer
follows Mr. Simpson.

The genus _Nephronaias_ as constituted by Mr. Simpson embraces two quite
distinct groups, divisible as follows.

_Nephronaias_ (_s. s._) embraces _plicatulus_, _persulcatus_, _melleus_,
_dysoni_, _ortmanni_, _ravistellus_, etc. Ample material of these two
latter species show that they are anatomically very closely allied to
_Elliptio_. There is no sexual difference of shape, and the gill is
gravid in its whole length. _Nephronaias_ differs from _Elliptio_ in its
sulcated disc, in its beak sculpturing, etc.

Included in _Nephronaias_ by Simpson are, however, shells of a totally
different type, such as _medellinus_, _gundlachi_, _sapotalensis_, etc.
These latter are sexually dimorphic, smoother, more generally rayed, and
the gravid uterus is of Lampsiline type.

The position of the dorsal scars within the beak cavities is different,
in the examples of the pseudo _Nephronaias_ seen by the writer.
_Nephronaias_ (_s. s._) possesses an (accessory?) adductor scar attached
to the frontal portion of the cardinal teeth, which is either absent or
obsoletely marked in the second assemblage. For this latter group the
writer, therefore, proposes to use the generic term of _Actinonaias_
Crosse and Fischer, 1893, type _U. sapotalensis_ Lea. The female of this
species has been described by Dr. Ortmann (1912). _Actinonaias_
embraces, besides the type, _medellinus_, _gundlachi_, (accepting
Simpson’s interpretation of this latter species), and others.

PSORONAIAS, Crosse and Fischer (1893). This group of remarkable shells,
embracing _crocodilarum_, _psoricus_, _semigranosus_, etc., was
provisionally treated by Simpson as a group of _Elliptio_, but their
remarkable sculpturing, and the deep beak cavities of some of their
species, led him to observe that it was possible that the group should,
after all, be placed in _Quadrula_.

I follow von Martens, in giving generic rank as above to the group. The
type is _Unio psoricus_. To this genus we are enabled to add a species
hitherto undescribed, under the name of


PSORONAIAS KUXENSIS, n. sp., PI. VII, figs. 1, 2.

Shell small, compressed, rough, brown, biangular. Length 50, height 30,
diam. 17 mm.

Shell hyperbolically rounded before, the extreme frontal point below the
centre. Dorsum slightly arched, descending behind the ligament to the
widely biangular posterior; the upper angle of which is midway the
height, the lower angle very little above the base, which is nearly
straight. The beaks are small, low, acute, approximate; and
_apparently_, concentrically ridged. Epidermis dark brown (olivaceous
and obsoletely rayed in the young), rough, the lines of growth numerous
and well impressed. The discs are covered with fine pustulations, more
pustular in front, biradially linear behind. The post ridge is low, but
distinctly double, making the shell biangulate behind. The teeth are
double in the left valve, single in the right. The cardinals are deeply
sulcate and stout. Laterals slightly curved or nearly straight,
separated by an interdentum. Nacre purple, beak cavities rather deep.
Dorsal scars numerous, extending in a row from above the centre of the
cavity down and forward upon the base of the cardinal teeth. Three well
impressed muscle scars in front, two behind, the latter almost
confluent. Habitat, Kux Creek, Chama, Guatemala. Collected by Mr. A. A.
Hinkley, Feb. 6, 1917. A few dead specimens were obtained on the bank of
the Isaibha River (Chama) of which the Kux Creek is a tributary. Type in
Academy Natural Sciences. Cotypes in collection of A. A. Hinkley, the
author and U. S. N. Museum.

I place this species in _Psoronaias_ Crosse and Fischer, type _U.
psoricus_, because of its evident relationship to _crocodilarum_, and
_distinctus_, differing mainly from the latter in size and degree of
inflation, being much inferior in both respects to _distinctus_.




                  ON THE RATE OF GROWTH OF POND UNIOS.


BY L. S. FRIERSON.

During the latter part of March 1916, the writer, for the purpose of
constructing a fish pond, excavated a barrow-pit near the bank of a
small creek, about ten feet wide, and at the time nearly dry. The
barrow-pit was perhaps one hundred feet long, fifty feet wide and three
feet deep. Early in April, 1916, the pit became full of water,
overflowing from the adjacent creek, and together with two subsequent
overflows, supplemented with seepage from the newly constructed fish
pond, the pit remained more or less full of water, until May 25, 1917,
when it was drained by a ditch into the nearby creek. From the dried
bottom of this pit some thirty Unios were picked up by the writer. Ten
of these were _Unio tetralasmus_ Say, and the rest were _T. texasensis_
Lea. All the specimens were of remarkably uniform size and appearance.
The _texasensis_ being about one and a half inches, and the
_tetralasmus_ two and a half inches long. Exact dimensions of a
_texasensis_: length 43, height 24, diam. 16 mm.; of _tetralasmus_ 75,
40, and 25 mm.

Both of these species had attained puberty. A female _texasensis_ had
its gills fairly full of young glochidia. A _tetralasmus_ had several
(three or four) ovisacs with a few (remaining) glochidia. In assigning
an age to these shells it is quite sure that the _tetralasmus_
discharges its glochidia in March and early April, so that when picked
up on May 25, these shells were just about fourteen months old, from the
date of discharge from their mother’s gills.

In the case of the _texasensis_ (which spawns somewhat later) it is
possible that these were dropped by fish of which, at least six species
obtained access to the pit on May 7, 1916 (on which date an overflow
occurred), thus making about thirteen months. At any rate the maximum
age of either species is fourteen months from their mother’s ovisacs.
One of the _U. tetralasmus_ is shown of natural size in Pl. VII, fig. 4.

Another observation concerning pond mussels might here prove of
interest. A large pond was cut into two by a railroad embankment, a
culvert preserving the level and providing communication between the
two. In the lower and larger pond a half-bushel of Yonkapin (_Nelumbium
luteum_) seed was sown. It was six years before these seeds germinated.
These plants, during the summer, cover the entire surface of the pond
with their broad peltate leaves. In this pond the writer planted a
colony of a dozen _Anodonta grandis_. Several years after, taking
advantage of extreme low water, the writer made a careful survey of
these twin ponds, with the result that hundreds of Anodons could be
found in the upper pond, but not a single one was found in the lower
pond. Either the shade killed the young shells, or else the
glochidia-laden fish avoided the shade of the lotus plants and
congregated in the upper pond (there are no Nelumbii in the upper pond).
Is not this avoidance of shade a reason for the paucity of unios in the
tropics?




                     A NEW SOUTH AFRICAN NESOPUPA.


BY H. A. PILSBRY.


NESOPUPA FARQUHARI, n. sp.

Among Pupillidae sent by Mr. J. Farquhar there is a new species from
Grahamstown which may be defined by comparison with _Nesopupa
griqualandica_ (Melv. and Pons.).[5] The new form is ovate, of about the
size of the other species, which it resembles in sculpture and in the
lamellae of the parietal wall and columella. The two palatal plicae are
subequal, the upper emerging to the lip, the lower one also long,
reaching to the inner edge of the peristome. There is a very small
nodule on the base of the columella. In _griqualandica_ the lower
palatal plica is short and very deeply immersed and there is a distinct
though small basal plica within the base, in front of the lower palatal
plica. In _griqualandica_ there is a deep sulcus outside, over the upper
palatal plica, and a flattening or short groove over the lower palatal;
but in _farquhari_ the sulcus is far less impressed except quite close
to the lip. The color is reddish brown. Length 1.65, diam. 0.9 mm.

Mr. Burnup’s figure 9, in Melvill and Ponsonby’s Revision,[6] may
perhaps represent this species, while their description in the same
paper appears to comprise both _griqualandica_ and _farquhari_, though
chiefly relating to the former. Their pl. I, figs. 8 and 10 represent
_griqualandica_. The new form is named in honor of one of the most
successful South-African collectors. It will be figured in the Manual of
Conchology.




                    A NEW GUNDLACHIA FROM GUATEMALA.


BY BRYANT WALKER.


GUNDLACHIA HINKLEYI, n. sp., Pl. I, figs. 10‒16; Pl. III, fig. 1.

Shell subovate, being much wider posteriorly, the anterior margin rather
shortly rounded, the right margin nearly rectilinear, but somewhat
diverging anteriorly, the left margin obliquely expanded and broadly
rounded, anterior margin wider and much more curved than the posterior;
apex very excentric, depressed and decidedly turned toward the right
side, bluntly rounded, smooth except for a few concentric wrinkles;
color a very pale corneous, nearly pure white; lines of growth rather
strong and irregular; anterior slope with strong radial striæ
originating below the septate growth and extending to the anterior
margin, similar striæ appear on the left lateral slope, but are
scarcely, if at all, visible on the right slope; the septate portion of
the shell is small in comparison with the adult expansion, it is narrow
and the posterior portion covered by the septum is free from and
projects over, but scarcely beyond, the posterior margin of the adult
aperture; the first growth of the shell from the septate form is
continued on the sides in a nearly direct continuation of the lateral
slopes of the septate shell for some little distance, the anterior slope
of this stage is also a continuation of the anterior slope of the
septate stage but owing to the oblique position assumed by the septate
shell is at first somewhat convex, as viewed laterally, later as the
side slopes begin to expand, the anterior slope is continued in a nearly
straight line to the margin; the left lateral slope of the adult shell
below the secondary constriction is concave at first, becoming nearly
straight toward the margin; the right lateral slope is less concave
above and straighter and more oblique than the left; owing to the small
size of the septum and consequent large aperture of the septate shell
and the narrow first growth of the adult shell there is no distinct
aperture to the septate portion visible in the adult shell from below,
the whole interior of the adult shell appears to pass, practically
unconstricted, directly into the septate portion; the posterior margin
of the adult shell narrow and somewhat abruptly expanded and reflected.

Length 5.5; width 3.75; alt. 1.75 mm.

The septate shell is oblong, the sides being nearly parallel, but
slightly expanding anteriorly, the right slightly convex and the left
slightly concave; the posterior margin is regularly rounded; the
anterior more broadly rounded; the apex depressed, bluntly rounded,
excentric, reaching nearly to the right margin, smooth except for slight
concentric wrinkles, lines of growth fine and regular; the anterior
slope is slightly convex; the very short posterior slope below the
projecting apex to the line of the septum is straight and oblique; the
right lateral slope is steep and nearly straight, the left slope very
convex; the septum is very short, being less than half of the length of
the septate shell, convex on its lower surface, the margin is very
short, being less than half of the length of the septate shell, convex
on its lower surface, the margin is very concave and on the right side,
extends further forward than it does on left, there does not seem to be
the distinct thickening of the margin so noticeable in other species;
aperture much larger than in any other species yet described.

Length 2; width 1.5; alt. .75 mm.

Type (43455 Coll. Walker) from the Maya Farm, Quirigua, Guatemala,
collected by A. A. Hinkley. Cotypes in the collection of Mr. Hinkley.

This fine species is the first from either Central or South America, of
which both the septate and adult forms are known.

It differs from all other described species except _crepidulina_ Guppy
in the small size of the septum and the consequent difference in the
position of the aperture of the septate stage in the adult shell. The
septum in the specimen figured appears very like the incomplete septum
in the North American species, but as the three adult specimens before
me are exactly alike in the position of the septate shell, this would
seem to be the normal condition in this species. The specimen figured,
which is 3.25 mm. in length, has apparently slightly passed the septate
stage and begun the growth of the constricted portion of the adult shell
and shows the beginnings of the radial striæ.

With the Gundlachias was associated a species of _Lævapex_, very like
the _excentricus_ Morelet. Whether it has any closer relations with the
_Gundlachia_ remains to be determined as the radula has not yet been
examined. While the general aspect of the two species, if such they be,
is very similar, the _Lævapex_ has a very much more acute apex than the
_Gundlachia_.

As shown by the figure, the radula of this species is quite typical of
the genus.




            A LIST OF SHELLS FROM THE EAST COAST OF FLORIDA.


BY BRYANT WALKER.

The late Dr. Charles A. Davis, the well known peat-expert of the U. S.
Bureau of Mines, in addition to his special acquirements in geology and
botany, was a good all-round zoologist and had a lively and unaffected
interest in the work that any of his friends might be carrying on in
that department. It was his kindly habit in his travels about the
country to preserve any specimens that he came across that seemed to him
likely to be of interest to any of his zoological friends. It will be
remembered that the conchologists owe to him the rediscovery of the long
lost _Planorbis multivolvis_ Case, (NAUT., XXI, p. 16), and also the
little _Lymnæa davisi_ Walker, (NAUT. XXII, p. 17), which bears his
name.

In the spring of 1911 Dr. Davis’ professional duties took him to Florida
and while there he collected quite a number of samples of “drift,” which
in due time came into my possession. Several of the localities
represented in the collection, such as Miami and St. Augustine, have
already been reported upon by previous collectors and there seems to be
no occasion to duplicate their work, but quite a number of the places
visited by Dr. Davis have not been covered by any of the previous
collectors in Florida and a record of the species found by him seems
worthy of publication as a contribution to the distribution of the
Mollusca along the east coast of the state.

I am indebted to Dr. George H. Clapp for the identification of the
Gastrocoptas and Vertigos.

The list of localities and species represented in the collection is as
follows:

                  MARSHES NEAR CHESTER SHOALS.

 _Euglandina rosea_ Fér.
 _Polygyra cereolus carpenteriana_ Bld.
 _Zonitoides minuscula_ (Binn.).
 _Zonitoides minuscula alachuana_ (Dall).
 _Vitrea dalliana_ (‘Simpson’ Pils.).
 _Pupoides modicus_ (Pfr.).
 _Gastrocopta rupicola_ (Say).
 _Gastrocopta pellucida hordeacella_ (Pils.).
 _Gastrocopta tappaniana_ (C. B. Ads.)?
 _Gastrocopta pentodon_ (Say).
 _Vertigo milium_ (Gld.).
 _Melampus coffeus_ (L.).
 _Detracia bulloides_ (Mont.).
 _Chrondropoma dentatum_ (Say).
 _Plecotrema cubense_ (Pfr.).
 _Blauneria heteroclita_ (Mont.).
 _Microtralia minuscula_ (Dall).
 _Truncatella clathrus_ Lowe.
 _Truncatella caribæensis pulchella_ Pfr.
 _Truncatella bilabiata_ Pfr.
 _Littoridina monroensis_ (Ffld.).

_Paludestrina?_ sp.? A single specimen that I can not approximate to any
of the described species.

This is the first record, I believe, for _Plecotrema cubense_ from the
mainland of Florida. Originally described from Cuba, it was listed from
the Bermudas by Dr. Pilsbry in 1900, (Trans. Conn. Acad., X, p. 504, pl.
lxii, fig. 11), and there figured by him for the first time. Both he and
Mr. John B. Henderson inform me that they have collected it on several
of the Keys and I am indebted to both of them for the opportunity of
comparing my specimen with theirs.

                 CHESTER SHOALS REFUGE STATION.

 _Euglandina rosea_ (Fer.).
 _Polygyra auriculata_ (Pfr.).
 _Polygyra uvulifera_ (Shutt.).
 _Polygyra cereolus_ (Mühlf.).
 _Polygyra cereolus carpenteriana_ (Bld.).
 _Polygyra cereolus septemvolva_ Say.
 _Polygyra cereolus volvoxis_ (Pfr.).
 _Praticolella jejuna_ (Say.).
 _Melampus coffeus_ (L.).
 _Detracia bulloides_ (Mont.)
 _Lymnaea humilis_ Say.
 _Physa cubensis_ Pfr.
 _Planorbis tumidus_ Pfr.
 _Planorbis alabamensis_ Pils.
 _Chrondropoma dentatum_ (Say).
 _Truncatella bilabiata_ Pfr.
 _Truncatella clathrus_ Lowe.
 _Littoridina monroensis_ (Ffld.).


           BETWEEN CHESTER SHOALS AND CAPE CANAVERAL.

 _Polygyra cereolus_ (Muhlf.).
 _Polygyra cereolus carpenteriana_ (Bld.).
 _Polygyra cereolus volvoxis_ (Pfr.).
 _Polygyra uvulifera_ (Shutt.).
 _Zonitoides minuscula_ (Binn.).
 _Pupoides modicus_ (Pfr.).
 _Gastrocopta pentodon_ (Say).
 _Gastrocopta pellucida hordeacella_ (Pils.).
 _Gastrocopta rupicola_ (Say).
 _Melampus coffeus_ (L.).
 _Detracia bulloides_ (Mont.).
 _Blauneria heteroclita_ (Mont.).
 _Chrondropoma dentatum_ (Say).
 _Truncatella bilabiata_ Pfr.
 _Truncatella clathrus_ Lowe.
 _Truncatella caribæensis pulchella_ Pfr.

 _Amnicola._ sp.? A single immature specimen.


                        CANAVERAL P. O.

 _Euglandina rosea_ (Fer.).
 _Polygyra cereolus septemvolva_ Say.
 _Polygyra cereolus volvoxis_ (Pfr.).
 _Polygyra cereolus carpenteriana_ (Bld.).
 _Pupoides modicus_ (Pfr.).
 _Helicina orbiculata_ Say.


                          EAU GALLIE.

 _Polygyra cereolus septemvolva_ Say.
 _Polygyra cereolus volvoxis_ (Pfr.).
 _Polygyra uvulifera_ (Shutt.).
 _Physa cubensis_ Pfr.
 _Helicina orbiculata_ Say var.


                     ISLAND OF EAU GALLIE.

 _Polygyra uvulifera_ (Shutt.).
 _Praticolella jejuna_ (Say).
 _Lymnaea humilis_ Say.
 _Physa cubensis_ Pfr.


                          PALM BEACH.

 _Euglandina rosea_ (Fer.).
 _Polygyra auriculata_ Say.
 _Polygyra cereolus carpenteriana_ (Bid.).
 _Strobilops floridana_ Pils.
 _Strobilops hubbardi_ (Brown).
 _Pupoides modicus_ (Pfr.).
 _Gastrocopta contracta_ (Say).
 _Gastrocopta rupicola_ Say.
 _Gastrocopta pellucida hordeacella_ (Pils.).
 _Gastrocopta pentodon_ (Say).
 _Vertigo milium_ (Gld.).
 _Vitrea dalliana_ (‘Simp.’ Pils.).
 _Vitrea indentata_ (Say).
 _Zonitoides arborea_ (Say).
 _Zonitoides minuscula_ (Binn.).
 _Zonitoides minuscula alachuana_ (Dall).
 _Guppya gundlachi_ (Pfr.).
 _Thysanophora granum_ (Streb.).
 _Physa cubensis_ Pfr.
 _Helicina orbiculata_ Say.


                           LONG KEY.

 _Euglandina rosea_ (Fer.).
 _Polygyra cereolus_ (Mühlf.).
 _Polygyra cereolus carpenteriana_ (Bid.).
 _Strophia incanum_ (Binn.).
 _Pupoides modicus_ (Pfr.).
 _Gastrocopta pentodon_ (Say).
 _Gastrocopta rupicola_ (Say)?
 _Gastrocopta pellucida hordeacella_ (Pils.).
 _Gastrocopta pellucida hordeacella_ (Pils.) var. Small form.
 _Thysanophora incrustata_ (Gld.).
 _Thysanophora granum_ (Streb.).
 _Thysanophora dioscoricola_ (Guppy).
 _Guppya gundlachi_ (Pfr.).
 _Varicella gracillima floridana_ Pils.
 _Succinea campestris_ Say?
 _Melampus coffeus_ (L.).
 _Detracia bulloides_ (Mont.).
 _Microtralia minuscula_ (Ball).
 _Lymnæa columella_ Say.
 _Physa cubensis_ Pfr.
 _Helicina tantilla_ Pils.
 _Chrondropoma dentatum_ (Say).
 _Truncatella caribæensis_ Sby.; Rve.
 _Truncatella caribæensis pulchella_ Pfr.
 _Truncatella clathrus_ Lowe.
 _Truncatella bilabiata_ Pfr.
 _Littoridina monroensis_ (Ffld.).

 _Amnicola. sp?_ A single specimen of a very small, globose form that
    may be an n. sp. Alt. 1 mm.




                   COLLECTING IN DIGBY, NOVA SCOTIA.


BY LILLIAN DYER THOMPSON.

While traveling through Nova Scotia and New Brunswick last summer, we
stayed for about six weeks at Digby, N. S. Digby is about 200 miles
northeast of Boston, and is situated near the Bay of Fundy, opposite St.
John, N. B. The town is located on the southeast shore of the Annapolis
Basin,—a sheet of water about twenty miles long and ten miles wide. This
basin is connected with the Bay of Fundy by a channel about
three-fourths of a mile wide at its greatest width. This channel, known
as Digby Gap, is noted for its rapid tides,—the rate of flow through the
Gap being about eight miles an hour. The tide fall at Digby is thirty
feet. The shores of the Basin are sandy, with the exception of the two
rocky promontories on each side of the Gap; the one which is nearest to
Digby being Point Prim. The town is on a small peninsula on either side
of which are two inlets of the Annapolis Basin, known as the Racquet, on
the west, and the Jacquet, on the east of Digby proper. On the ebb tide
these are almost dry, exposing long mud flats.

There is one island in the Basin, about opposite the Gap and at the
mouth of Bear River, called Bear Island. From this a long bar extends,
called Bear Island Bar, which is covered to a depth of about six feet at
low water, and is covered with eelgrass.

Near the Yacht Club pier were found many _Polinices heros_, and their
red-brown “sand-collars.” In the Jacquet were many _Litorina littorea_
and _Litorina rudis_. On the exposed beach, nearer the town, we found
_Mytilus edulis_. On the rocks, in the Racquet, we found _Thais
lapillus_ and a host of _Acmaea testudinalis_ ranging in size from
one-eighth of an inch to about an inch in diameter. In the mud, at the
base of the rocks, were a multitude of _Buccinum undatum_, _Neptunea
decemcostata_, ranging in size from one-eighth of an inch to about an
inch in diameter. In the mud, at the base of the rocks, were a multitude
of _Buccinum undatum_, _Neptunea decemcostata_, and _Colus stimpsoni_,
all alive and half-buried. Some dead specimens of _Aporrhais
occidentalis_ were also found, five of them being full-grown.

On the suggestion of Capt. Danforth, we constructed a dredge, and
endeavored to dredge Bear Island Bar from his motor-boat. Here we found
quantities of _Lacuna vincta_, _Alectrion obsoleta_, _Cylichna alba_,
and two _Polinices triseriata_.

There were some soldiers encamped at Digby, and they used to gather
_Litorina littorea_ and steam and eat them, without any flavoring. They
sometimes ate _Thais lapillus_ also. One day, after a rain, we found two
_Helix hortensis_ crawling along the road.




  A NEW TYPE OF THE NAYAD-GENUS FUSCONAIA. GROUP OF F. BARNESIANA LEA.


BY A. E. ORTMANN.

During the study of the nayad-fauna of the upper Tennessee, the present
writer found that there exists, in this region, a peculiar type of
shells, belonging to the genus _Fusconaia_, the various forms of which
have been described previously under a great number of specific names,
which, however, seem to belong all to one species. In addition, among
material received from L. S. Frierson from the Ozark Mountains, a form
was discovered which presented the same structure.

The oldest name for the upper Tennessee form is _Unio barnesianus_ Lea.
A more detailed account of its various phases is to be given elsewhere,
and it suffices here to mention only those forms which belong here.
According to obesity, I distinguish three local, or ecological races:


                  1. FUSCONAIA BARNESIANA (Lea) 1838.

_U. barnesianus_ Lea, ’38. _U. meredithi_ Lea, ’58. _U. pudicus_ Lea,
’60. _U. Lyoni_ Lea, ’65. _U. tellicoensis_ Lea, ’72. _U. lenticularis_
Lea, ’72.

As the normal (most abundant) forms we may regard _U. meredithi_,
_pudicus_ and _lenticularis_, which differ from each other only in the
development of the rays (topotypes examined). _U. barnesianus_ is a
slightly more elongated individual, with poorly developed rays. _U.
tellicoensis_ (topotypes examined) is a _lenticularis_ slightly more
swollen; and _U. Lyoni_ forms the transition toward var. _tumescens_,
having a little more elevated beaks, greater obesity, and rather
distinct rays.


             2. FUSCONAIA BARNESIANA BIGBYENSIS (Lea) 1841.

_U. bigbyensis_ Lea, ’41. _U. estabrookianus_ Lea, ’45. _U. fassinans_
Lea, ’68. _Pleurobema fassinans rhomboidea_ Simpson, ’00.

The most frequent form is _fassinans rhomboidea_ (topotypes examined),
with rays poorly developed. _U. bigbyensis_ has more distinct rays; _U.
estabrookianus_ (topotypes examined) is an old, overgrown form, without
rays; _U. fassinans_ is founded upon an individual (type examined, also
topotypes), which is exceptionally elongated, without rays.


             3. FUSCONAIA BARNESIANA TUMESCENS (Lea) 1845.

_U. tumescens_ Lea, ’45. _U. crudus_ Lea, ’71. _U. radiosus_ Lea, ’71.

_U. tumescens_ is the most typical form, greatly swollen, with more or
less developed rays; _U. radiosus_ (type and topotypes examined) is less
swollen, but for the rest like _tumescens_; _U. crudus_ (topotypes
examined) lacks rays, and has much eroded beaks, but stands close to
_radiosus_.

The mutual relations of these forms may be understood by the help of the
following key. Only the three largest divisions are to be regarded as
varieties, in the other forms the characters are merely individual,
although specimens representing only one (or a few) of these “forms”
often prevail at a given locality.

 a_{1}. Flat, compressed, dia. of shell less than 40 per cent of the
    length (var. _bigbyensis_).

   b_{1}. No rays, or rays obscure, color of epidermis brown, dark.

     c_{1}. Rhomboid in shape.

       d_{1}. Large.           _Estabrookianus._

       d_{2}. Smaller.       _Fassinans rhomboidea._

     c_{2}. More ovate, tapering behind.     _Fassinans._

   b_{2}. Rays distinct, well developed over most of the disk. Ground
      color of epidermis lighter. _Bigbyensis._

 a_{2}. Moderately convex, dia. 40‒49 per cent of length. _Barnesiana
    typica._

   b_{1}. Beaks not elevated, shape trapezoidal, rhomboid, or subovate.

     c_{1}. Dia. about 41 or 42 per cent; size small.

       d_{1}. Shape somewhat elongate (trapezoidal); rays obscure.
          _Barnesianus._

       d_{2}. Shape shorter (rhomboidal).

         e_{1}. Rays obscure.       _Lenticularis._

         e_{2}. Rays present, color of epidermis lighter.

           f_{1}. Rays few.        _Meredithi._

           f_{2}. Rays numerous.      _Pudicus._

     c_{2}. Dia. about 45 per cent; larger. Shape subovate. Rays obscure.
        _Tellicoensis._

   b_{2}. Beaks more elevated, shape subtriangular. Dia. 46 per cent,
      with rather distinct rays. _Lyoni._

 a_{3}. Much swollen, dia. over 50 per cent. Beaks elevated. (var.
    _Tumescens_).

   b_{1}. Without rays. Dia. 51 per cent. Beaks much eroded. _Crudus._

   b_{2}. With rays. Dia. about 56 per cent or more.

     c_{1}. Dia. about 56 per cent.        _Radiosus._

     c_{2}. Dia. about 64 per cent.       _Tumescens._

As to the geographical distribution, it should be briefly stated that
the swollen forms (a_{3}) inhabit the largest rivers; the compressed
forms (a_{1}) are found in the headwaters, and the intermediate forms
(a_{2}) belong to the streams of moderate size. Intergrades are
frequent.


                              ANATOMY.[7]

All these shells have the same, and an extremely characteristic and
unique structure of the soft parts, so that there is not the slightest
question that they belong together. I have examined the soft parts of
some 200 specimens in the field, and over three dozens have been
preserved in alcohol, and have been examined at leisure in the
laboratory. They include representatives of the three main varieties,
and of practically all of the individual variations.

_Gravid females_ have been found on the following dates: May 11, ’13;
May 15, ’13; May 16, ’13; May 20, ’13; May 20, ’14; May 22, ’14; May 25,
’14; July 5, ’13; July 9, ’13; July 10, ’13; July 13, ’13; July 14, ’13.
_Glochidia_ have been observed on May 20, ’14 (immature), and July 14,
’13. Thus this species evidently is a summer breeder (tachytictic).

The soft parts are those of the genus _Fusconaia_: the _supraanal_ is
separated from the _anal_ by a very short mantle-connection, which is
absent (or torn?) in rare cases. Inner lamina of inner gills free from
abdominal sac. All four gills are marsupial. Placentae well developed
and subcylindrical.

_Branchial opening_ with well developed papillae, _anal_ with distinct,
but small papillae. _Palpi_ subfalciform, posterior margins connected at
base only.

While thus the _Fusconaia_ structure is typically developed, this
species is quite unique in its color. This concerns chiefly the color of
the gonads, eggs, and placentae.

The soft parts are often uniformly pale, whitish, but may shade to
orange, and the orange is most prominent on foot, adductors, and
mantle-margin; but the paler tints prevail, and often the orange is
replaced by yellowish or brown. The gills are pale, but are generally
suffused with blackish. The gonads are brown to red, mostly of a
peculiar dull lavender color in the female, and the latter color, or
purplish brown, is the prevailing color of the eggs and placentae. The
charged gills become thus rather dark purple, or purple-brown, shading
sometimes to dull red or blackish, in other cases to brownish, brownish
pink, brick-red, or even pale brown. These are very peculiar tints, by
which this species is easily recognized in the field: four marsupial
gills of this blackish-purple color are not known in any other Nayad.

_Glochidia_ have been found only in specimens belonging to the
headwaters variety (_barnesiana bigbyensis_). They are subelliptical,
slightly higher than long, L. 0.15, H. 0.16 mm.

Although a true _Fusconaia_, this species (or group of forms) stands
isolated within the genus, in characters of the shell as well as in the
soft parts. It differs from the species of the _subrotunda_-group (ind.
_ebena_, _pilaris_ etc.) very markedly by its smaller size and by the
very shallow beak cavities. The forms of the _undulata_-group (incl.
_flava_, and the _cuneolus_- and _cor_forms) have generally also
somewhat deeper beak cavities, and the shell has a more or less distinct
posterior ridge, with a flattening or a shallow groove in front of it,
characters which are missing in the _barnesiana_-group. As has been
pointed out, in the latter group, the color of eggs and placentae is
remarkable: in all other forms of _Fusconaia_, this varies from white to
bright red.

I introduce here another species, in order to show that
the _barnesiana_-type is also represented outside of the
Cumberland-Tennessee drainage, namely in the Ozarks.


                   FUSCONAIA OZARKENSIS (Call) 1887.

_F. ozarkensis_ Call, Pr. U. S. Mus. 10, ’87, p. 499, pl. 27. Tr. St.
Louis Ac. 7, ’95, p. 33, pl. 18. _Lampsilis ozarkensis_ Meek & Clark,
Bur. Fisher. Doc. no. 759, ’12, p. 18. _Pleurobema utterbacki_ Frierson,
in: Utterback, Naiad. Missouri (Amer. Midland Natural 4, 1916, p. 86,
pl. 5, pl. 20, f. 63).

I have specimens from James River, Galena Stone Co., Mo., and White
River, Cotter and Norfolk, Baxter Co., Ark., donated by L. S. Frierson
and collected by A. A. Hinkley on July 30 and Aug. 2 and 5, ’14, A
number of specimens (8) were preserved in alcohol, coll. July 30 and Aug
2, which all were gravid females, and one of each date had glochidia.
This marks probably the end of the breeding season, and the species is
tachytictic.

There is some confusion with regard to this species. After the first
description by Call, it has not again been recorded, except by Meek and
Clark, and I believe, the identification of these authors (supported by
B. Walker) is correct. But I think that other authors have seen this
form, but have not recognized it, and, for instance, Simpson’s
_pannosus_ and _subellipticus_ (regarded as varieties of _Pleurobema
argenteum_ and _breve_ respectively) are also this. Frierson’s
_utterbacki_ is surely this, since my specimens were thus labeled by
Frierson.

Walker, Frierson, and Simpson (in part) believe this to be a
_Pleurobema_, and not a _Lampsilis_ (see also Simpson, ’00, p. 557, and
’14, p. 131), and this comes nearest to the truth, in fact, it is the
most plausible assumption to be made from the study of the shell alone.
The shell “resembles a very elongated _Quadrula coccinea_,” according to
Meek and Clark, and the comparison with _Pleurobema argenteum_ and
_breve_ (which, by the way, are synonyms), made by Simpson, is
significant. We must keep in mind that Call’s fig. 4 represents the
normal shape of the shell, while his fig. 1 is rather abnormal, and
possibly does not belong here at all. These two figures by no means
represent the female and male, as Call believes.

The investigation of the soft parts has shown that this actually is a
_Fusconaia_. Corresponding, both in soft parts and shell, to the
_barnesiana_-type of the upper Tennessee region. _F. ozarkensis_ differs
from _barnesiana_ by the more elongated (subtrapezoidal) outline of the
shell, more anterior beaks, and the weak development of the rays, which
are faint at the best, and often entirely absent. A swollen form of it
is not known to me, but specimens from White River are slightly more
convex than those from James River (farther up). Also Utterback’s
quotation of Frierson (p. 87, footnote) make it probable that there are
differences in obesity.


                                ANATOMY.

_Supraanal_ opening probably separated from the _anal_ by a short
mantle-connection, but in all my specimens this is torn by rough
handling. Inner lamina of inner gills free from abdominal sac. All four
gills marsupial in the female. _Placentae_ well developed and
_subcylindrical_.

Anal opening with small papillae, branchial opening with well developed
papillae. _Palpi_ as usual, their posterior margins connected for about
one third of their length or less.

As to the color of the soft parts, which is so characteristic in
_barnesiana_, not much can be said, since my material has been too long
in alcohol. But in most of my specimens the gills are yet distinctly
suffused with black. The placentae have been rendered whitish, but here
and there traces of a dark stain are preserved (which is disappearing
gradually). It is quite possible that the color of the placentae
originally was similar to that of _barnesiana_.

The _glochidia_ are subelliptical, slightly higher than long; L. O. 15,
B. O. 18, thus agreeing with those of _F. barnesiana_.




             NOTE ON THE RELATION OF SNAIL FAUNA TO FLOODS.


BY A. RICHARDS.

During the years 1911 to 1916, while the writer was a member of the
faculty of the University of Texas, a series of incidental observations
on the snail fauna of Waller Creek was made. These observations have now
come to an end due to the change of residence of the observer. It seems
not unwise, therefore, to publish a short note on the subject in the
hope that the facts recorded, although fragmentary, may have a bearing
on the work of some other follower of snail life.

Waller Creek is a small stream near the University of Texas at Austin.
It is some four miles in length and empties into the Colorado River at a
distance of perhaps two miles below the University. That portion of the
stream close to the University between Fifteenth and Twenty-seventh
Streets, was most closely observed, but data was also collected from the
region below. During the hot months, from about July 1st to October 1st
usually, the stream is dry, or water is to be found only in an
occasional pool; during the rest of the year the water flows to a depth
of a few inches. The bed is scoured out of limestone (Austin Chalk) and
has for much of its length a solid flat rock bottom. The banks of the
creek have in general a gradual slope. In time of flood and during heavy
rains, this stream rises very rapidly and quickly becomes bank-full, so
that the water rushes down in a torrent, the roar of which may at times
be heard for a distance of some blocks. The fall of the creek is
considerable, being about 75 feet in two miles from Twenty-seventh
Street to the Colorado, and this fall in connection with the shape of
the bed gives to the current in times of flood a tremendous force.

During the first two years of this observation, 1912‒1913, the snail
population of the creek in its middle stretches was dense. There were in
particular two species very thickly represented, _Planorbis lentus_ and
_Physa halei_. So numerous were they that one could in a few moments
within a very few feet gather a pint of either kind. Wherever a little
ripple or a tiny waterfall occurred were many snails oriented in
relation to the current, their heads pointing into it. Elsewhere in the
more quiet water they were also to be found, but in less numbers. These
conditions obtained especially in the early spring; as the breeding
season, which in that latitude extends over half the year, passes by,
the snails of course become much less numerous.

It is to be noted that previous to the time when the snails had become
so abundant, there had been no heavy rains of sufficient importance to
be recorded since 1908. Excessive rains occurred in May 1908, November
and May 1907, June and March 1905, May and April 1904, July and February
1903, July and November 1902. There was a very severe flood in the creek
in April 1900. It will be seen that between the time when my
observations began and the last excessive rain considerable time had
elapsed and the snails had had the opportunity to reinstate themselves
in the creek, assuming that they had suffered in those floods as they
have done in the later ones.

In the fall of 1913 there were two floods of unusual proportions in the
creek. In October it rose very rapidly, but shortly subsided, and in
November, at the time when the entire state was visited by the most
severe flood since 1869, it was again subjected to a very thorough
scouring. Excessive rains fell on several consecutive days, and streams
in the entire Colorado watershed were out of their banks.

After the heavy rains of the earlier part of the month there were
several days upon which the rainfall, while comparatively light, was
sufficient to keep the creek much higher than its normal level. When the
water finally subsided to its normal amount the bed was covered
completely with a layer of detritus and soft green humus and algae from
a half an inch to an inch in thickness. This deposit and the acids
formed from it have been the cause of a much more rapid disintegration
of the limestone than had been the case in the immediately preceding
years. Loose pieces of limestone which were exposed to the action of the
water had in many cases fallen apart by the end of January. Further
rises occurred on April 27 and on May 20th, 1914, but were not
sufficient to remove all of the accumulated layer of detritus.

In January 1914, a search for snails where they had before been numerous
failed to reveal a single specimen of _Planorbis_ and less than half a
dozen _Physa_. Even in the deeper pools they could scarcely be found.
Later in the spring in the lowest part of the stream a number of very
small _Physa_, as well as some clusters of eggs were found. The force of
the current had been so great as to wash the snails down to the river,
and it is possible that the condition of the water due to the
decomposing humus may have affected those which were able to escape the
flood danger. That some of the Physa were left after the flood may be
attributed to their pointed shape which decreases the amount of force
that the water was able to exert on them as compared with that on the
flat Planorbis shells. Except as noted above in April and May 1914, the
conditions in the creek remained as normal.

In January 1915, Physa has again made its appearance in the middle parts
of the stream, although in small numbers only. Diligent search, however,
failed to reveal a single Planorbis. The snails which were present were
found only under fair-sized rocks where they were well protected; they
did not occur out in the open stream as had been the case when the creek
was more densely populated with snails.

In April 1915, on the 22d and 24th, Waller Creek was swept by three
scouring floods which devastated the entire bottoms. The water rose
higher during the night than it had at any time since 1886; bridges were
washed away and much damage done. The bottom of the creek was again
washed clean except under the larger stones and in deep holes in the
bed. Snails were not observed in any numbers following this flood during
the rest of that year. Early in January 1916, however, Physa had again
appeared fairly abundantly where they had formerly been very thick, in
the region just above the University; later in the spring they became
quite numerous here. In January of this year the first Planorbis were
found that had been seen in the creek since the autumn floods of 1913.
Between Fifteenth and Sixteenth Streets in a pocket containing
good-sized stones over which the water flows rather swiftly a number of
specimens were taken, although none were found above or below this
locality. It is noted that below this region the creek is frequently
covered with oily scum and that it receives the refuse from the
adjoining properties. Except after high water which would clean it out,
the creek in this region would hardly be expected to support much snail
life. It must be supposed either that the Planorbis had made their way
up to Sixteenth Street during the short time following the floods before
the water became badly contaminated, or else that in this particular
place a few specimens from the previous years had withstood the floods
and reproduced themselves in sufficient numbers to be noticeable in
January. Of these two suppositions the latter seems much the more
rational.

After the flood of 1915 the water subsided very quickly so that a new
layer of humus and algae was not deposited, but that the bed was again
restored to its former condition of a clean smooth rock bottom. Upon the
return to this condition the snail population increased very rapidly,
and at the time when the last observation was made in the early summer
of 1916, seemed in a fair way to return to the condition of 1912.

It seems to the writer that the slow return of the snails during the
year 1914 was due not only to the repeated rains of the fall and winter
of 1913‒14, but also to the condition of the creek bed at this time.
Although the heavy rains of 1915 were more severe, they were confined to
one month, and the creek bed was left in a very much cleaner condition
than during the preceding year.

The conditions of life which obtain now in Waller Creek are those of a
new life region. This must of necessity be so in an intermittent stream
to a certain extent, but owing to the flood conditions here they are
doubly so.

The chief facts of interest in regard to the habits of snails as shown
by these observations, are these: 1, The snails of both species are to
be found commonly in uncontaminated water which is running at a fairly
rapid rate, and the most common orientation is with the heads pointing
up stream; 2, The snail population in any stream is subject to wide
fluctations depending upon flood conditions; 3, Physa because of its
shape is less affected by floods than Planorbis; 4, The return of the
snail population to a given stream is determined not only by the
frequency and severity of the floods, but also by the condition of the
bottom of the stream after the subsidence of the high water; 5, The
snails thrive best where there is a constantly renewed supply of clean
water which contains little decaying vegetation.

 _Wabash College, Crawfordsville, Ind._




                         WILLIAM BULLOCK CLARK.


Dr. William Bullock Clark, professor of geology in the Johns Hopkins
University, eminent for his contributions to geology, died suddenly from
apoplexy on July 27, at his summer home at North Haven, Maine.

Wm. Bullock Clark was born at Brattleboro, Vermont, December 15, 1860.
Since 1894 he was professor of geology in Johns Hopkins University. In
1896 Professor Clark organized the Maryland Geological Society, and has
been State Geologist since that time. The admirable volumes on
paleontology of Maryland, issued under his direction, are widely used by
conchologists interested in fossil mollusks. This series of reports will
be his enduring memorial. Professor Clark’s chief paleontological
interest was in the _Echinoidea_, upon which he published several
monographs.




                         PUBLICATIONS RECEIVED.


A MONOGRAPH OF WEST AMERICAN MELANELLID MOLLUSKS. By Paul Bartsch (Proc.
U. S. Nat. Museum, Vol. 53, pp. 295‒356, pls. 34‒39, Aug. 1917). This
completes the discussion of the West American mollusks of the
super-family Pyramidelloideae, comprising the family Pyramidellidae,
which has been previously treated, and the Melanellidae here considered.
The former are readily distinguished by having the “nepionic whorls
sinistral and tilted; the axis of the early whorls usually being at
right angles to that of the succeeding turns, in the first of which the
nuclear whorls are frequently quite strongly imbedded.” In the latter
the early whorls are dextral and never tilted or immersed. A review of
the work done in this group is followed by the descriptions of the
species, including forty-nine new species and one new genus
_Eulimostraca_. The illustrations are excellent.

                  *       *       *       *       *

NEW AND LITTLE KNOWN SPECIES OF SOUTH AMERICAN MUSSELS OF THE GENUS
DIPLODON. By William B. Marshall (Proc. U. S. Nat. Museum, Vol. 53, pp.
381‒388, Pls. 50‒55, August, 1917). Two new species _Diplodon
felipponei_ and _D. fortis_ are described and figured, together with six
species described by Mr. C. T. Simpson in his Descriptive Catalogue of
the Naiades and not previously figured.

                  *       *       *       *       *

NOTES ON THE SHELLS OF THE GENUS EPITONIUM AND ITS ALLIES OF THE PACIFIC
COAST OF AMERICA. By William H. Dall (Proc. U. S. Nat. Museum, Vol. 53,
pp. 471‒488, August, 1917). An interesting account of the various groups
and subgenera is followed by descriptions of forty-two new species.

The name Pictoscala is proposed for a section, type _Scalaria lineata_
Say.

                  *       *       *       *       *

STUDIES ON AUSTRALIAN MOLLUSCA. PT. XIII. By C. Hedley (Proc. Linn. Soc.
New South Wales, 1916, vol. 41, pt. 4, pp. 680‒719, pls. 46‒52, issued
April 4, 1917). The author’s notes under _Tridacna gigantea_ Perry are
of such general interest that we quote them in part. “Under the name of
_Chama gigas_ the father of Natural History seems to have embraced the
whole of the modern genus _Tridacna_. For the name _gigas_, as
restricted to a single species, the candidates are the shell
subsequently named _squamosa_ by Lamarck and a huge species whose valves
in the Ulrica Museum, together weighed 498 pounds.

“After careful examination, Hanley decided that the furbelowed clam,
such as Reeve has figured for _T. squamosa_, ought rightly to bear the
name _gigas_. He based his verdict on the ground that the actual shell
owned by Linné as representing _gigas_, is the Lamarckian _squamosa_,
and that to this apply most of the literary references. Linnean
contemporaries such as Born, Regenfuss and Chemnitz, while making casual
references to the giant, all agree in figuring and describing _squamosa_
as the Linnean _gigas_.

“Discriminating in 1819 between the species his predecessors had
confused, Lamarck unlawfully used the name _gigas_ for the largest form,
while for the Linnean _gigas_ he proposed _squamosa_. Attentive to the
remarks of Hanley, Hidalgo in 1903, renamed the biggest species _T.
lamarcki_. But in 1811, Perry had already used the name _Chama gigantea_
for ‘the largest shell at present known.’ As the young of the giant has
not yet been traced to the adult, it is still possible that _squamosa_
is a juvenile deeper-water form of the large intertidal and abraded
_gigantea_.

“The heaviest known are a pair weighing 550 lbs., which Cuvier and
Lamarck relate were presented by the Venetian Republic to Francis I.
These still exist, their edges bound with brass, as holy-water basins in
the cathedral of St. Sulpice, in Paris.

“The photographs of Saville Kent show the giant clams in their natural
position on the Great Barrier Reef, where they occur free and exposed at
low tide, standing on their umbones, and showing their brightly colored
mantle and so-called eyes as they gape.”

There are many other interesting notes bearing on nomenclature, and the
animals of Australian species. Six new species are described and
twenty-nine species figured.—C. W. J.

                  *       *       *       *       *

AN ANNOTATED LIST OF SHELLS FROM NORTHERN MICHIGAN. By Mina L. Winslow
(Occasional papers, Mus. Zool., Univ. Mich., No. 42, July 1, 1917) a
list of sixty-five species from Schoolcraft, Alger and Chippewa
counties, also a list from Isle Royale.




                                 NOTES.


THE OLDROYD COLLECTION.—Mr. and Mrs. J. S. Oldroyd have given their
collection of shells to the Leland Stanford Jr. University, and are now
permanently employed in the Museum, Mrs. Oldroyd being the curator. The
collection has been placed in the Department of Geology and Mining. The
Stanford alumni purchased the collection and library of the late Henry
Hemphill, which, with the Law collection and several others, forms an
unusually fine working series. Mr. and Mrs. Oldroyd have spent about
eight weeks at Friday Harbor, Puget Sound and British Columbia making
large collections for the Stanford University, California Academy of
Science and University of California.

                  *       *       *       *       *

NORTH CAROLINA LAND SHELLS.—The following species of land shells were
picked from leaf-mold collected at Spruce Pine, Mitchell Co., North
Carolina, by Samuel G. Gordon while on a mineralogical excursion. The
specimens are in the collection of the Acad. Nat. Sci., Phila.,
_Gastrocopta contracta_ Say, _G. pentodon_ Say, _Circinaria concava_
Say, _Polita indentata_ Say, _Taxeodonta lamellidens_ Pils.,
_Gastrodonta elliotti_ Redf., _G. guldaris_ Say, _Euconulus sterkii_
Dall., _Punctum pygmæum_ Drap., _Carychium exile_ Lea.—E. G. VANATTA.

                  *       *       *       *       *

A CORRECTION.—In my little paper, “Descriptions of New West American
Marine Mollusks and Notes on Previously Described Forms,” Proc. U. S.
Nat. Mus., Vol. 52, pp. 670‒671, plate 46, figure 2, 1917, I published
_Cerithiopsis (Cerithiopsis) helena_ from Panama, type Cat. No. 204128,
U. S. N. M. Mr. Vignal, of Paris, has been kind enough to call my
attention to the fact that the same combination was used by O. Boettger
in 1901 for a fossil in his contribution “Zur Kenntnis der Fauna der
mittelmiocänen Schichten von Kostej im Krassò-Szörényer Komitat,” in
“Verhandlungen und Mitteilungen des siebenbürgischen Vereins für
Naturwissenchaften zu Hermannstadt,” p. 128, 1901. It is therefore
necessary to bestow a new designation on my shell, and it may be known
as _Cerithiopsis (Cerithiopsis) anaitis_.—PAUL BARTSCH.

                  *       *       *       *       *

ALBINISTIC EPIPHRAGMOPHORA FIDELIS.—A few days ago, I had two hours in
Gladstone Park. The Park is wooded, and there are large moss-covered
rocks. _E. fidelis_ was out freely. I found one light one. The one sent
you some years ago was uniform in color. This one shows two distinct
dark narrow bands around the lower whorl, but not showing anywhere else.
This is the fourth one I have found in the Park in twenty years or more,
though I have been there often.

                                         —J. G. MALONE, _Portland, Ore._

                  *       *       *       *       *

The many friends of DR. HERMANN VON IHERING will hear with deep regret
that he has been removed by political intrigue from his position of
Director of the MUSEU PAULISTA at Sao Paulo, Brazil. This museum was
founded by Dr. von Ihering. His eminence as a zoologist and unceasing
activity as an investigator of the South American fauna, had won for it
an honorable place among scientific institutions. We understand that his
successors are men without knowledge of the biological sciences. As the
only scientific assistant, Mr. Rudolph von Ihering has resigned, it
appears that the scientific activity of the State Museum of Sao Paulo
has come to an end—a real calamity to American zoology and paleontology.

Dr. von Ihering is located at present at Hansa de Joinville, State of
Santa Catharina. He is in good health, and is engaged in the preparation
of his work: “Die biogeographischen Grundgesetze,” several chapters of
which will deal with mollusks.—H. A. P. & C. W. J.

[Illustration:

  PLATE VII
]

 1, 2. PSORONAIAS KUXENSIS FRIERSON.

    3. EPIPHRAGMOPHORA CALLISTODERMA PILS. & FERR.

    4. UNIO TETRALASMUS SAY.

 5, 6. ZACHRYSIA RAMSDENI PILS.

    7. Z. EMARGINATA PFR.

-----

Footnote 1:

  NAUTILUS, vol. xx, pp. 58‒60.

Footnote 2:

  NAUTILUS, xxvi, pp. 51‒55, 1912.

Footnote 3:

  In a later work Ortmann classifies both _ventricosa_ and
  _cohongoronta_ as varieties of _ovata_ Say.

Footnote 4:

  The relations of mollusks to fish in Oneida Lake. By Frank Collins
  Baker. Technical Publication No. 4, New York State College of Forestry
  at Syracuse University. Pp. 366. Syracuse, N. Y., 1916. We are
  informed that it may be obtained free by those interested in the study
  of Mollusca by applying to the dean of the college, Dr. Hugh P. Baker.

Footnote 5:

  _Pupa griqualandica_ M. and P., 1893; the specimens used being from
  Pretoria.

Footnote 6:

  Ann. Mag. N. H. (8), i, p. 76, pl. i, 1908.

Footnote 7:

  In NAUTILUS, 28, 1914, p. 31, I have described the anatomy of
  “_Pleurobema fassinans_.” This is a mistake: the shells examined
  belong to _Pleurobema_ all right, but are the form known as _U.
  argenteus_ Lea, which belongs to the _oviforme-group_, and should be
  called: _Pleurobema oviforme argenteum_ (Lea). These will be treated
  more fully elsewhere.

------------------------------------------------------------------------




                          TRANSCRIBER’S NOTES


 1. Silently corrected typographical errors.
 2. Retained anachronistic, non-standard, and uncertain spellings as
      printed.
 3. Footnotes have been re-indexed using numbers and collected together
      at the end of the last chapter.
 4. Enclosed italics font in _underscores_.