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    PROCEEDINGS

    OF THE

    WASHINGTON ACADEMY OF SCIENCES

    VOL. III, PP. 111-138.      MARCH 26, 1901




MAMMALS COLLECTED BY DR. W. L. ABBOTT ON THE NATUNA ISLANDS.

BY GERRIT S. MILLER, JR.


About three months during the spring and summer of 1900 were spent by
Dr. W. L. Abbott in exploring the Natuna Islands in the South China
Sea.[1] Specimens were collected at the following localities: Pulo
Midei, or Low Island (May 23-26), Pulo Seraia (May 29), Sirhassen
Island (June 1-10), Pulo Subi (June 12-13), Pulo Lingung (June
17-19), Bunguran, or Great Natuna Island (June 24-July 31) and Pulo
Laut, or North Natuna Island (August 5-13). About 265 mammals were
obtained, all of which have been presented to the United States
National Museum. This paper contains an account of these, and is
published here by permission of the Secretary of the Smithsonian
Institution.

Two extensive collections of mammals had been made on the Natuna
Islands previous to Dr. Abbott's visit, the first by Mr. A. Everett
during September and October, 1893, the second by Mr. Ernest Hose
during July, August, September and October, 1894. These have
formed, either wholly or in part, the basis of several papers,[2]
which constitute the literature relating to the mammals of the
islands.[3] Twenty-eight land mammals have been recorded as actually
represented by specimens, though several others are mentioned which
the collectors ascertained to occur. Dr. Abbott secured forty-four
species, but failed to obtain seven[4] of those previously taken.
The total number of mammals collected on the islands thus becomes
fifty-one. This increase is due, in part to the recognition of a
larger number of insular forms than has been admitted by previous
writers, but also to a considerable extent to the actual addition
of species not hitherto taken. Species new in the latter sense
are distinguished in the present paper by absence of reference to
previous records.

In regard to the faunal relationships of the Natunas, whether
predominantly Bornean or Peninsular, about which much has been
written,[5] it may be said that this collection, together with
much of the other work recently done by Dr. Abbott, tends to show
that there is greater general uniformity in the mammalian fauna of
Borneo, the Malay Peninsula, and the intervening islands than has
been hitherto supposed. It seems unprofitable therefore to offer
conjectures as to the probability of greater nearness of the Natuna
mammals as a whole to those of Borneo or to those of the Malay
Peninsula.


MANIS JAVANICA Desmarest.

    1895. _Manis javanica_ THOMAS and HARTERT, Novitates Zoologicæ,
    II, p. 492. December, 1895 (Bunguran).

An adult male was taken on Bunguran, June 24, 1900. Total length 914;
head and body 508; tail 406.


TRAGULUS BUNGURANENSIS sp. nov.

_Type._--Adult male (skin and skull) No. 104604 U. S. National
Museum. Collected on Bunguran Island, North Natunas, July 9, 1900.
Original number, 547.

_Characters._--Color pattern essentially as in _Tragulus nigricans_
Thomas, from Balabac. Size equal to that of _T. canescens_ from the
Malay Peninsula, therefore much greater than in the Balabac animal.

_Color._--Back uniform ochraceous, fading to buff on sides, the
hairs everywhere gray at base. Both back and sides everywhere
darkened by black hair tips, but these never sufficiently abundant
to produce a dark shading in excess of the ochraceous. The relative
proportion of the dark wash to the light under color is precisely
the same as in _Tragulus canescens_ and _T. napu_ (from Linga
Island) but the black is less conspicuous than in the Bornean form
of _T. napu_. Legs, except white area on inner side, like back
but slightly brighter and less shaded with black. Entire dorsal
and lateral surface of neck clear black to base of hairs, a few
ochraceous specks visible on close scrutiny, particularly at sides
near throat markings. On shoulders this black area fades abruptly
into color of back; on head it passes forward between ears and
eyes nearly to muzzle. Cheek, region between eye and ear, and line
extending forward over eye to muzzle and separating black median
stripe from naked loral space, ochraceous, essentially like that of
legs. Throat markings as in _Tragulus nigricans_, but white stripes
apparently even more restricted. Region occupied by posterior white
stripes black, continuous with that of neck, but distinctly speckled
with ochraceous. Region occupied by anterior stripes ochraceous,
continuous with that of cheeks and somewhat less pure and more
speckled with black. White stripes as follows: (_a_) One on each
side of naked chin area. These are about 50 mm. in length and never
more than 10 mm. in breadth, but occasionally so narrow as to break
up into two or more spots. They are separated from naked chin patch
by an ochraceous stripe slightly broader than the white. Chin area
narrowly and discontinuously bordered with white, especially in
front. (_b_) Two posterior lateral stripes varying from 50 mm. to
80 mm. in length, and never more than 12 mm. wide. They are strongly
convergent anteriorly, and sometimes nearly joined together in front
by a median spot. These white stripes are always separated from the
anterior stripes by an ochraceous median area varying from 10 mm. to
25 mm. in width. (_c_) A median stripe lying between the posterior
lateral stripes. Posteriorly this stripe is as wide as the lateral
stripes, but it quickly narrows and sometimes disappears at middle
of latter, though usually represented again by the median spot
already referred to. In none of the specimens is this stripe broad
and continuous anteriorly to level of front of lateral stripes as in
Nehring's figure of the throat markings of _T. nigricans_.[6] Collar
narrow, ochraceous grizzled with black. It is seldom more than 25
mm. in width; therefore much narrower than indicated by Nehring's
figure. Behind the collar is a whitish gray median area continuous
laterally with narrow light stripe down inner side of fore legs. This
light area is sometimes divided by a dark median line joining collar
with buff of belly. Belly and chest buff, essentially like that of
sides, with which it forms no contrast in color. As on the sides
the buff is clouded by black hair tips, but the hairs are scarcely
if at all gray at base. On chest the dark hair tips tend to form a
median stripe, which is sometimes sharply defined and continuous with
the ochraceous line occasionally dividing white of breast. A clear
whitish area slightly larger and better defined than that of breast
occupies region between hind legs. It is continuous with white stripe
down inner side of hind legs. This stripe is usually divided on thigh
by encroachment of the surrounding ochraceous. Tail silky white below
and at tip, essentially like back above.

_Skull._--The skull of _Tragulus bunguranensis_ fully equals that of
_T. canescens_ in size, and distinctly exceeds that of the Bornean
form of _T. napu_. It is much larger than that of _T. nigricans_,
which proves to be a medium sized species like _T. rufulus_. In
general form the skull agrees so closely with that of _Tragulus
canescens_ that it is only to be distinguished by its slightly
greater relative breadth and smaller, less inflated audital bullæ.
As compared with the skull of _Tragulus nigricans_,[7] that of _T.
bunguranensis_ is much larger (distance from back of occiput to
front of canine 103 instead of 92, zygomatic breadth 53 instead of
45), and the braincase is more conspicuously ridged for muscular
attachment. That part of the braincase immediately above posterior
root of zygoma is more conspicuously inflated. Otherwise I can detect
no salient differences in the skulls of the two animals.

_Teeth._--The teeth are uniformly larger than those of _Tragulus
nigricans_, but in form they present no characters of importance. As
compared with _T. canescens_ the premolars both above and below are
conspicuously more robust, a character in which the Bunguran animal
agrees with the Bornean form of _Tragulus napu_.

_Measurements._--External measurements of type: total length 647;
head and body 571; tail vertebræ 76; hind foot 146; hind foot
without hoofs 128. Average and extremes of five adults from the type
locality: total length 643 (628-673); head and body 566 (558-584);
tail vertebræ 77 (70-89); hind foot 142 (140-146); hind foot without
hoofs 126 (124-128).

Cranial measurements of type: greatest length 114; basal length 107;
basilar length 100; occipito-nasal length 106; length of nasals 32;
diastema 13 (9);[8] zygomatic breadth 52 (46); least interorbital
breadth 33 (28); greatest breadth of braincase above base of zygomata
38 (33); mandible 91 (78); maxillary toothrow (alveoli) 38 (34);
mandibular toothrow (alveoli) 44 (39); anterior upper premolar 7 ×
3.8 (6.4 × 3); middle lower premolar 7.2 × 3 (5.8 × 2.4).

_Weight._--Weight of type 3.8 kg.; of two other males 3.6 kg. each.
Two adult females weigh respectively 3.6 kg. and 4.2 kg.

_Specimens examined._--Six, all from the type locality.

_Remarks._--_Tragulus bunguranensis_ is so distinct from the other
known species as to require no detailed comparisons.


TRAGULUS sp.

Two specimens from Sirhassen Island are too immature for
determination. Apparently they represent a member of the _napu_
group, allied to that occurring in Borneo. The throat markings show
no approach to those of _Tragulus bunguranensis_.


TRAGULUS JAVANICUS (Gmelin).

    1894. _Tragulus javanicus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 660. September, 1864 (Bunguran).

    1895. _Tragulus javanicus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 492. December, 1895 (part, specimens from
    Bunguran).

Six specimens from Bunguran.


TRAGULUS PALLIDUS sp. nov.

    1895. _Tragulus javanicus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 492. December, 1895 (part, specimen from Pulo
    Laut).

_Type._--Adult female (skin and skull) No. 104616 U. S. National
Museum. Collected on Pulo Laut, North Natuna Islands, August 11,
1900. Original number 625.

_Characters._--Smaller than _Tragulus javanicus_ from Borneo or
Bunguran and very pale in color. Black clouding of upper parts
inconspicuous, but dark nape band well defined.

_Color._--Back and sides light ochraceous-buff everywhere clouded by
the blackish hair-tips, but these never in excess, except perhaps
along middle of back and across lumbar region. Flanks, shoulders,
neck, outer surface of legs and narrow line dividing color of
sides from that of belly pale ochraceous. Nape band clear black,
sharply defined from color of sides but quickly fading into that of
shoulders. Top of head dull dark brown. A faint pale stripe over and
in front of eye. Throat markings normal, the dark bands like neck.
Collar very narrow. Under parts and inner surface of legs white. A
faint yellowish shade along middle of belly. Tail white beneath and
at the tip, ochraceous faintly shaded with brown above.

_Skull._--The skull of the type, though fully adult and with all the
teeth distinctly worn, is smaller than in Bunguran specimens so young
that the posterior molars are still below the rim of the alveoli. In
form, however, it shows no marked peculiarities, though in general it
appears to be somewhat broader in proportion to its length than that
of the Bunguran animal.

_Teeth._--Teeth as in specimens of _Tragulus javanicus_ from Bunguran
except that the premolars, both above and below, are shorter and
broader, a difference which may prove to be an individual peculiarity
only.

_Measurements._--External measurements of type: Total length 539;
head and body 444; tail vertebræ 95; hind foot 107; hind foot without
hoofs 95.

Cranial measurements of type: Greatest length 90 (94[9]); basal
length 83 (87); basilar length 78 (82); occipito-nasal length 83
(89); length of nasals 25 (29.6); diastema 9.2 (9.8); zygomatic
breadth 41.4 (40); least interorbital breadth 26.4 (25); breadth
of braincase over roots of zygomata 29.4 (28.4); mandible 72 (75);
maxillary toothrow (alveoli) 31.6 (34); first upper premolar 6.4 ×
2.8 (7 × 2.6); mandibular toothrow (alveoli) 35.8 (38).

_Specimens examined._--One, the type.

_Remarks._--This is a pallid form of _Tragulus javanicus_, a species
which apparently shows very little tendency to become differentiated
into local races. The characters of the Pulo Laut animal were pointed
out by Thomas and Hartert in 1895.


SUS NATUNENSIS sp. nov.

    1894. _Sus_ sp. THOMAS and HARTERT, Novitates Zoologicæ, I, p.
    660. September, 1894 (Bunguran).

    1895. _Sus_ sp. THOMAS and HARTERT, Novitates Zoologicæ, II, p.
    492. December, 1895 (Bunguran).

_Type._--Adult female (skin and skull) No. 104856 U. S. National
Museum. Collected on Pulo Laut, North Natuna Islands, August 6, 1900.
Original number 609.

_Characters._--Externally much like the Tenasserim form of _Sus
cristatus_, but smaller; body brownish in marked contrast with black
legs and face; skull conspicuously shorter and broader.

_Fur._--The fur throughout consists of bristles with no admixture
of softer hairs. The bristles are everywhere less stiff than in the
Tenasserim pig, but the difference is most noticeable in the mane,
which, though well developed (about 80 mm. in length), is composed of
bristles very slightly coarser than those of the surrounding parts,
and of not more than half the diameter of the corresponding hairs in
females of _S. cristatus_. Muzzle, chest, belly and ears nearly bare.

_Color._--General color black, clear and unmixed with brown on legs,
throat, and face, but elsewhere heavily overlaid with brownish buff,
particularly on back and sides. The brownish wash ceases abruptly
just in front of ears, leaving the face and cheeks clear black. A
conspicuous dull buff streak 100 mm. long and about half as wide at
middle extends back from angle of mouth to level of posterior canthus
of eye. It is sharply outlined above by black of cheeks, and below by
that of chin. A faint buffy mark beneath eye. Tail like back.

_Skull._--The skull while much shorter than that of _Sus cristatus_
from Tenasserim is actually broader. As a result the width across
postorbital processes is contained only about three times in
occipito-nasal length, as opposed to nearly four times in the related
species. Similarly the zygomatic breadth slightly exceeds one half of
the basilar length, while in _Sus cristatus_ it is less than half.
Width of palate between middle molars almost exactly one sixth
distance from posterior edge of palate to front of premaxillaries
(measured along median line). In _Sus cristatus_ the palatal width
is contained nearly seven times in the same distance. Dorsal profile
of skull slightly concave near base of nasals. Zygomata heavier and
deeper than in _Sus cristatus_. Audital bullæ noticeably smaller and
less inflated than in the Tenasserim pig. Mandible shorter and much
more robust than that of _Sus cristatus_, the outward bulge of the
ramus a little behind middle of toothrow greatly accentuated.

_Teeth._--As the teeth of the two specimens of _Sus natunensis_
are much worn, while those of the only skulls of _Sus cristatus_
at hand are not fully grown, it is impossible to make any accurate
comparisons. The smaller size of the Natuna pig's teeth is, however,
evident for the length of the entire upper toothrow does not equal
that of _S. cristatus_ without the posterior molar. The crown of the
middle upper molar appears to be more nearly square in outline than
that of the Tenasserim pig, but in the very different condition of
the specimens it would be unsafe to assume that this character is
constant.

_Measurements._--External measurements of type; total length 1294;
head and body 1117; tail vertebræ 177; height at shoulder 558; hind
foot 220 (170); ear from meatus 100; width of ear 75.

Cranial measurement of type: greatest length 295 (332[10]);
occipito-nasal length 282 (316); basal length 245 (275); basilar
length 235 (263); length of nasals 135 (157); width of both nasals
together posteriorly 34 (33); median length of bony palate 168 (183);
width of bony palate at middle of second molar 30 (29); breadth
between tips of postorbital processes 87 (87); least interorbital
breadth 64 (65); zygomatic breadth 130 (133); occipital breadth 58
(62); occipital depth 100 (103); least depth of rostrum between
canine and incisor 33 (39); mandible 225 (232); depth of mandible
through coronoid process 104 (110); depth of ramus at front of first
molar 40 (41); maxillary toothrow to front of canine (alveoli) 113
(131[11]); mandibular toothrow to front of canine (alveoli) 120
(138); crown of first upper molar 12 × 13 (18 × 16); crown of second
upper molar 18 × 18 (22 × 16).

_Weight._--Weight of type, 40 kg.; weight of adult female from Pulo
Lingung, 35 kg.

_Specimens examined._--Two, one from Pulo Laut, the other from Pulo
Lingung.

_Remarks._--While the two specimens agree in all essential
characters they differ in numerous minor details. The skin from
Pulo Lingung is somewhat darker than the type, but the difference
is due to the shade of the brown wash, not to any extension of the
black. The skull of this specimen is more rounded posteriorly than
that of the type, and the rostrum is shorter. Both specimens show
conclusively that their relationships are with the _Sus cristatus_ of
the Malay Peninsula and not with the _S. longirostris_ of Borneo, a
case which finds an exact parallel in the giant squirrels.


MUS INTEGER sp. nov.

_Type._--Adult male (skin and skull) No. 104837 U. S. National
Museum. Collected on Sirhassen Island, South Natunas, June 7, 1900.
Original number 455.

_Characters._--A large robust species with coarse but not spinous
fur. Relationships with _Mus validus_ Miller, from Trong, Lower Siam,
and _Mus mülleri_ Jentink from Sumatra. Differs from the former in
smaller size and in the absence of the anterior outer tubercle of the
last upper molar, and from the latter in larger size, and yellowish
brown (not white) underparts.

_Color._--Back and sides a fine grizzle of black and dull
ochraceous (the exact shade intermediate between the ochraceous and
ochraceous-buff of Ridgway), the two colors nearly equally mixed on
back, but the ochraceous in excess on sides. Underparts and inner
surface of legs buff. An ill defined drab-gray median line from
throat to pubic region. Head darker and more glossy than back, the
cheeks distinctly washed with gray. Lips and chin drab-gray. Feet an
indefinite brown, darker on metapodials. Ears essentially naked, dark
brown. Tail dark brown throughout. Underfur gray (Ridgway, pl. II,
No. 8), becoming paler on under parts where it fades irregularly into
the general buff.

_Fur._--The fur is exactly as in _Mus validus_, that is the grooved
bristles are so slender that their true nature is not apparent
without use of lens. On middle of back the mass of the fur is about
17 mm. in length, the long terete hairs scattered through it reaching
about 30 mm. On rump the fur is longer but not conspicuously so, and
there is no noticeable increase in length or abundance of the terete
black hairs.

_Tail, feet and mammæ._--Tail slightly more coarsely scaled than in
_Mus validus_; 9 rings to the centimeter at middle. Hairs scarcely
noticeable except toward tip, where they somewhat exceed the breadth
of the rings.

Feet heavy and robust. Thumb short, with a flat blunt nail. Soles and
palms naked, the former with six well developed tubercles, the latter
with five.

Mammæ, p. 2--2, i. 2--2 = 8.

_Skull._--In general appearance the skull of _Mus integer_ resembles
that of _Mus validus_.[12] It is shorter (greatest length about 51
instead of 55) and the rostrum is relatively broader and deeper.
Audital bullæ similar in form to those of _Mus validus_, but the
surface less irregular. Region between anterior bases of zygomata
broader than in _Mus validus_ so that the arches are more nearly
parallel.

_Teeth._--The teeth are relatively as well as actually smaller
than in _Mus validus_ and the enamel pattern is normal, that is,
the posterior upper molar consists of two transverse folds, and an
anterior internal tubercle. There is no trace of the supplementary
outer tubercles of the corresponding tooth of _Mus validus_.

_Measurements._--External measurements of type: total length 463;
head and body 235[13] tail vertebræ 228;[13] hind foot 48 (45); ear
from meatus 19; ear from crown 15; width of ear 15. In adult male
topotype: total length 462; head and body 234;[13] tail vertebræ
228;[13] hind foot 46 (44); ear from meatus 21; ear from crown 16;
width of ear 16.

Cranial measurements of type: greatest length 52 (55);[14] basal
length 45 (48.6); basilar length 41.6 (45.6); palatal length 23
(26); least width of palate between anterior molars 5 (5); diastema
14 (14.6);[15] length of incisive foramen 8 (9); combined breadth
of incisive foramina 3 (3.6); length of nasals 21 (22.6); combined
breadth of nasals 6 (6.2); zygomatic breadth 25 (28); interorbital
breadth 8 (8); mastoid breadth 19 (19); breadth of braincase above
roots of zygomata 18.8 (20); depth of braincase at anterior border of
basi-occipital 12.8 (15); frontopalatal depth at posterior extremity
of nasals 12.8 (13.4); least depth of rostrum immediately behind
incisors 10 (10); maxillary toothrow (alveoli) 9.6 (11); width of
front upper molar 3 (3); mandible 30 (31); mandibular toothrow
(alveoli) 9 (10).

_Specimens examined._--Four, three from the type locality, and one
from Pulo Lingung.

_Remarks._--This rat is probably a near relative of the Bornean _Mus
mülleri_ of Thomas.[16] The specimen from Pulo Lingung does not
differ appreciably from the others.


MUS SABANUS Thomas.

    1887. _Mus sabanus_ THOMAS, Ann. and Mag. Nat. Hist., 5th ser.,
    XX, p. 270. October, 1887 (Mt. Kina Balu, Borneo).

    1894. _Mus sabanus_ THOMAS and HARTERT, Novitates Zoologicæ, I,
    p. 658. September, 1894 (Bunguran).

Thirteen skins and one extra skull, all from Bunguran. There is
little probability that this rat is the same as the true _Mus
sabanus_ of Borneo.


MUS RAJAH Thomas.

    1894. _Mus hellwaldi_ THOMAS and HARTERT, Novitates Zoologicæ,
    I, p. 658. September, 1894 (Bunguran).

    1894. _Mus rajah_ THOMAS, Ann. and Mag. Nat. Hist., 6th ser.,
    XIV, p. 451. December, 1894 (Mount Batu Song, Borneo).

    1895. _Mus rajah_ THOMAS, Novitates Zoologicæ, II, p. 26.
    February, 1895 (Revised determination of Bunguran specimens).

Six specimens (one in alcohol) from Bunguran, two from Pulo Lingung,
one from Pulo Laut, four (one in alcohol) from Sirhassen, and one (in
alcohol) from Pulo Midei. It is doubtful whether these series are
referable to one species or whether any of them are the true Bornean
_Mus rajah_. The material is not wholly satisfactory, and I have been
unable to examine specimens from Borneo.


MUS NEGLECTUS Jentink.

    1894. _Mus rattus_ var. THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 658. September, 1894 (Bunguran).

    1895. _Mus neglectus_ THOMAS and HARTERT, Novitates Zoologicæ,
    II, p. 492. December, 1895 (Bunguran).

Five specimens from Pulo Lingung, one from Pulo Midei, and nine from
Sirhassen. In the absence of Bornean material, I follow Thomas and
Hartert in referring the Natuna rats of the '_alexandrinus_' type to
_Mus neglectus_.


SCIUROPTERUS EVERETTI Thomas.

    1894. _Sciuropterus phayrei_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 660. September, 1894 (Bunguran).

    1895. _Sciuropterus everetti_ THOMAS, Novitates Zoologicæ,
    II, p. 27. February, 1895 (Revised determination of Bunguran
    specimens).

    1895. _Sciuropterus everetti_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 490. December, 1895 (Bunguran).

Two specimens, both from Bunguran; an immature male taken July 4, and
an adult female taken July 21, 1900.


PETAURISTA NITIDULA Thomas.

    1894. _Pteromys nitidus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 660. September, 1894 (Bunguran).

    1895. _Pteromys nitidus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 490. December, 1895 (Bunguran).

    1900. _Petaurista nitidula_ THOMAS, Novitates Zoologicæ, VII,
    p. 592. December 8, 1900 (Bunguran).

Seven specimens from Bunguran.


SCIURUS PROCERUS sp. nov.

    1894. _Sciurus tenuis_ THOMAS and HARTERT, Novitates Zoologicæ,
    I, p. 659. September, 1894 (Bunguran).

    1895. _Sciurus tenuis_ THOMAS and HARTERT, Novitates Zoologicæ,
    II, p. 492. December, 1895 (Bunguran).

_Type._--Adult male (skin and skull) No. 104698 U. S. National
Museum. Collected on Bunguran Island, North Natunas, July 18, 1900.
Original number 574.

_Characters._--Externally similar to _Sciurus tenuis_ though somewhat
smaller. Skull very much smaller and relatively broader than in the
related species.

_Color._--The color is exactly like that of _Sciurus tenuis_ from
Singapore.

_Skull and teeth._--Except that it appears to be broader throughout,
relatively to its length, the skull of _Sciurus procerus_ is
essentially a miniature of that of _S. tenuis_, as the braincase
shows none of the tendency to increased depth characteristic of the
Bornean animal. Ratio of rostral depth to distance between middle of
interparietal and lower rim of audital bulla, 50. This ratio is 49 in
_S. tenuis_.

_Measurements._--External measurements of type: total length 235;
head and body 140; tail vertebræ 95; hind foot 35 (33). Average and
extremes of four specimens from the type locality: total length 239.5
(235-247); head and body 140; tail vertebræ 99.5 (95-107); hind foot
35.2 (34-36.5); hind foot without claws 32.9 (31.8-34).

Cranial measurements of type: greatest length 34 (38);[17] basal
length 28.6 (32); basilar length 26 (29); palatal length 14.6 (16);
diastema, 7.6 (8.8); length of nasals 10.4 (11.4); greatest breadth
of nasals 4.8 (5.6); interorbital breadth 12 (12.6); zygomatic
breadth 20.8 (21); greatest breadth of braincase 17 (17.6); cranial
depth from middle of interparietal to lower rim of audital bulla 14
(15); least depth of rostrum 7 (7.2); mandible, 20 (21); maxillary
toothrow (alveoli) 6 (7); mandibular toothrow (alveoli), 6 (7).

_Specimens examined._--Six, all from the type locality.

_Remarks._--This species is immediately distinguishable from its
allies by its small skull, scarcely larger than that of _Funambulus
macclellandi_.


SCIURUS NATUNENSIS (Thomas).

    1894. _Sciurus lowi_ THOMAS and HARTERT, Novitates Zoologicæ,
    I, p. 659. September, 1894 (Sirhassen).

    1895. _Sciurus lowi natunensis_ THOMAS, Novitates Zoologicæ,
    II, p. 26. February, 1895 (Revised determination of Sirhassen
    specimen).

    1895. _? Sciurus lowi natunensis_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 491. (Bunguran and Pulo Laut.)

Four specimens from Sirhassen. The average and extreme measurements
are as follows: total length 222 (215-229); head and body 135
(133-140); tail vertebræ 86 (82-89); hind foot 33.6 (33-35); hind
foot without claw 31.5 (30.5-32).


SCIURUS LINGUNGENSIS sp. nov.

    1895. _? Sciurus lowi natunensis_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 491. (Bunguran and Pulo Laut.)

_Type._--Adult male (skin and skull) No. 104693 U. S. National
Museum. Collected on Pulo Lingung off southern extremity of Bunguran,
North Natuna Islands, June 19, 1900. Original number 494.

_Characters._--Externally similar to _Sciurus natunensis_ (Thomas),
but slightly larger (hind foot with claws 36 instead of 33.6). Skull
larger than that of _S. natunensis_, the audital bullæ much broader
anteriorly.

_Color._--The color is precisely as in _Sciurus natunensis_, and
therefore requires no detailed description.

_Skull._--Skull larger than that of _Sciurus natunensis_ (see
measurements) but not different in general form. The audital bullæ
are, however, readily distinguishable by the much greater development
of the anterior inner lobe. In _Sciurus natunensis_ this lobe is so
small as scarcely to form any part of the general contour of the
bulla. In _S. lingungensis_ it is nearly equal to the anterior outer
lobe, together with which it imparts a distinctly triangular outline
to the ventral aspect of the bulla.

_Measurements._--External measurements of type: total length 229;
head and body 140; tail vertebræ 89; hind foot 36 (33.7); ear from
meatus 12; ear from crown 7. A second specimen from the type locality
gives precisely the same measurements.

Cranial measurements of type: greatest length 38 (36);[18] basal
length 33 (31); basilar length 30 (29); palatal length 17 (16);
greatest length of nasals 11 (10); greatest width of both nasals
together 5 (5); interorbital breadth 12 (11.4); zygomatic breadth
22.4 (20); mastoid breadth 17 (16.6); depth of braincase at anterior
edge of basi-occipital 13.6 (13); mandible 23 (22); maxillary
toothrow (alveoli) 6.4 (7); mandibular toothrow (alveoli) 7 (7).

_Specimens examined._--Two, both from the type locality.

_Remarks._--While _Sciurus lingungensis_ is scarcely distinguishable
from _S. natunensis_ by external characters alone, size of the skull
and form of the audital bullæ are clearly diagnostic. Both species
from the Natunas are separated from the Bornean _S. lowi_ Thomas by
their well developed ears, and shorter broader rostral portion of
skull.


SCIURUS LUTESCENS sp. nov.

    1894. _Sciurus notatus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 659. September, 1894 (part, specimens from
    Sirhassen).

_Type._--Adult male (skin and skull) No. 104668 U. S. National
Museum. Collected on Sirhassen Island, South Natunas, June 3, 1900.
Original number 429.

_Characters._--Allied to _Sciurus notatus_, but considerably smaller
than the Bornean representative of the species. Colors very pale,
the under parts buff or cream-buff (Ridgway, pl. v, nos. 13 and 11)
irregularly tinged with gray.

_Color._--Entire dorsal surface of body and tail a fine grizzle
of black and cream-buff, the individual hairs black with two or
three cream buff rings. On tail the grizzle is less fine than on
back, and it shows a faint tendency to resolve itself into obscure
cross bands. On sides of body and on head the cream-buff brightens
to buff. Cheeks and muzzle buff, scarcely grizzled. Feet slightly
yellower than sides, under parts and inner surface of legs pale
buff, palest anteriorly and laterally (where it about matches the
cream-buff of Ridgway) brightest along median line. Under side of
tail dull ochraceous-buff slightly grizzled with black. Pencil not
different from rest of tail. Between the colors of sides and belly
are the usual longitudinal stripes. The outer of these is about 5
mm. in width, and cream-buff in color. The inner is about twice as
wide, and black, but much obscured by a thick sprinkling of bluish
gray hairs. Outer surface of ears concolor with neck, inner surface
like cheeks. The sprinkling of bluish gray hairs on sides of belly
extends irregularly forward to axilla and inner side of front leg,
occasionally to throat and chin.

_Skull._--As compared with the Bornean form of _Sciurus notatus_, the
skull of _S. lutescens_ is much smaller (greatest length about 45
instead of 50) the rostrum is relatively shorter and broader, and
the audital bullæ are less elongate antero-posteriorly. Teeth as in
_Sciurus notatus_ except that they are uniformly smaller.

_Measurements._--External measurements of type: total length 355;
head and body 177; tail vertebræ, 177; hind foot 45 (41). Average and
extremes of six specimens from the type locality: total length 356
(329-375); head and body 186 (177-196); tail vertebræ 170 (152-178);
hind foot 43.8 (41-45); hind foot without claws 40.7 (39-42).

Cranial measurements of type: greatest length 45.4 (50.4)[19];
basal length 39 (43); basilar length 36.4 (41); palatal length 20
(23); palatal width between middle molars 6 (6); greatest length
of nasals 13 (14.8); greatest width of both nasals together 6.6
(7); interorbital breadth 15.4 (17); mastoid breadth 21 (21);
zygomatic breadth 26 (29); depth of braincase at anterior edge of
basi-occipital 16 (16.8); mandible 28 (30); maxillary toothrow
(alveoli) 8 (9); mandibular toothrow (alveoli) 8 (9).

_Specimens examined._--Seven (one in alcohol), all from the type
locality.

_Remarks._--This squirrel is recognizable among the members of
the _S. notatus_ group by its light colors, and particularly by
the pallor of the under parts. In the latter characteristic it is
approached by the form inhabiting Pulo Laut, but with this exception
it is unique among the fulvous bellied species. The six specimens
show no variation worthy of note.


SCIURUS SERAIÆ sp. nov.

_Type._--Adult male (skin and skull) No. 104660 U. S. National
Museum. Collected on Pulo Seraia, South Natuna Islands, May 29, 1900.
Original number 415.

_Characters._--Most nearly related to the small, pallid, _Sciurus
lutescens_ from Sirhassen Island, but upper parts slightly less pale,
and under parts and pale side stripe buff-yellow, the former without
admixture of gray.

_Color._--Upper parts as in _Sciurus lutescens_ except that the
pale bands on the hairs are more nearly buff than cream-buff. Tail
essentially as in _S. lutescens_ but a shade less pale. Under parts
buff-yellow darkening irregularly to dull orange-buff. Dark side
stripe broad and well defined.

_Skull._--The skull closely agrees with that of _Sciurus lutescens_
in both size and form, though it is perhaps even broader in
proportion to its length. Teeth as in _S. lutescens_.

_Measurements._--External measurements of type: total length 368;
head and body 197; tail vertebræ 171; hind foot 44 (40). Average and
extremes of four specimens from the type locality: total length 347
(323-368); head and body 184 (171-197); tail vertebræ 163 (152-171);
hind foot 43.7 (43-45); hind foot without claws 40.1 (39.5-41).

Cranial measurements of type: greatest length 45; basal length
38.6; basilar length 36; zygomatic breadth 26.4; least interorbital
breadth 17; mandible 28; maxillary toothrow (alveoli) 8.6; mandibular
toothrow (alveoli) 8.6.

_Specimens examined._--Four, all from the type locality.

_Remarks._--As might be expected from the geographic position of the
island it inhabits, _Sciurus seraiæ_ differs from the Bornean _S.
notatus_ in much the same way as the Sirhassen representative of the
group. It is readily distinguishable from the Sirhassen animal by the
different color of the under parts. In color _Sciurus seraiæ_ closely
resembles _S. abbottii_ of the Tambelan Islands. The latter is,
however, a much larger animal, with a longer and relatively narrower
skull.


SCIURUS RUTILIVENTRIS sp. nov.

_Type._--Adult male (skin and skull) No. 104658 U. S. National
Museum. Collected on Pulo Midei (Low Island), South Natuna Islands,
May 24, 1900. Original number 405.

_Characters._--Size slightly greater than that of _Sciurus lutescens_
and _S. seraiæ_, but not equal to that of the Bornean or Bunguran
representatives of _S. notatus_. Color above as in _S. seraiæ_. Under
parts bright clear orange-rufous.

_Color._--Color exactly as in _Sciurus seraiæ_ except that the pale
side stripe is light cream-buff and the under parts are bright orange
rufous. Tail without trace of red suffusion.

_Skull and teeth._--The skull and teeth are a trifle larger than in
_Sciurus lutescens_ and _S. seraiæ_, but the difference is scarcely a
tangible one.

_Measurements._--External measurements of type: Total length 368;
head and body 190; tail vertebræ 178; hind foot 45 (41). Average and
extremes of seven specimens from the type locality: total length 356
(330-368); head and body 186 (178-190); tail vertebræ 173 (165-184);
hind foot 45.5 (43-48); hind foot without claws 42.2 (39.5-45).

_Specimens examined._--Seven, all from the type locality.

_Remarks._--This squirrel is remarkable among the Natuna members of
the _S. notatus_ group for the brilliant color of its under parts. In
this respect it surpasses all of the related forms with which I am
acquainted. The red color is, however, strictly confined to the body,
showing no tendency to spread to the tail as in _S. miniatus_ of the
Malay Peninsula.


SCIURUS RUBIDIVENTRIS sp. nov.

    1894. _Sciurus notatus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 659. September, 1894 (part, specimens from
    Bunguran).

    1895. _Sciurus notatus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 491. December, 1895 (part, specimens from
    Bunguran).

_Type._--Adult female (skin and skull) No. 104671 U. S. National
Museum. Collected on Bunguran Island, North Natunas, June 22, 1900.
Original number 498.

_Characters._--Size and general appearance both above and below
as in the Bornean form of _Sciurus notatus_, but red of under
parts brighter, and cheeks and chin distinctly less fulvous than
surrounding parts. Skull with broader, deeper braincase than in the
Bornean animal.

_Color._--The color so closely resembles that of the Bornean _Sciurus
notatus_ that no detailed description is necessary. Under parts
ochraceous-rufous, fading to tawny on throat, everywhere lighter and
more tinged with red than in the Bornean animal. In the latter the
color of the under parts extends forward to lips and also strongly
suffuses the cheeks and sides of head which are only a shade browner
than the throat and conspicuously more fulvous than top of head and
sides of neck. In _Sciurus rubidiventris_ the cheeks and lips are
noticeably suffused with gray so that they form a distinct contrast
with both throat, top of head and sides of neck.

_Skull._--The skull agrees in general size with that of the Bornean
animal, and is therefore much larger than in the three species from
the South Natunas. It is distinguishable by greater general breadth
and by the depth of the braincase, which perceptibly exceeds that of
_S. notatus_.

_Measurements._--External measurements of type: total length 380;
head and body 209; tail vertebræ 171; hind foot 49 (44.5). Averages
and extremes of seven specimens from the type locality: total
length 378 (368-393); head and body 208 (203-222); tail vertebræ
173 (165-184); hind foot 49.3 (48-50); hind foot without claws 45.7
(44.5-47).

Cranial measurements of type: greatest length 52.4 (50.4);[20]
basal length 44 (43); basilar length 41 (41); palatal length 23
(23); palatal width between middle molars 6 (6); greatest length of
nasals 15 (14.8); greatest width of both nasals together 7.2 (7);
interorbital breadth 18.2 (17); mastoid breadth 23 (21); breadth
of braincase above roots of zygomata 24 (22); zygomatic breadth
30.4 (29); depth of braincase at anterior edge of basi-occipital
17.8 (16.8); mandible 29 (30); maxillary toothrow (alveoli) 9 (9);
mandibular toothrow (alveoli) 9 (9).

_Specimens examined._--Seven, all from the type locality.

_Remarks._--In both size and general color this squirrel more closely
resembles the Bornean representative of the group than it does
either of the three forms from the South Natunas. Its relationships,
however, appear to be rather with the race inhabiting Singapore
Island than with any of its near geographic allies, _Sciurus
lautensis_ excepted.


SCIURUS LAUTENSIS sp. nov.

    1895. _Sciurus notatus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 491. December, 1895 (part, specimens from
    Pulo Laut).

_Type._--Adult female (skin and skull) No. 104683 U. S. National
Museum. Collected on Pulo Laut, North Natuna Islands, August 6, 1900.
Original number 612.

_Characters._--Size slightly less than that of _Sciurus
rubidiventris_ and color conspicuously pallid. Upper parts as in _S.
lutescens_; lower parts nearly as in _S. seraiæ_ but rather less
dull; pale side stripe much less yellow than belly. Skull as in
_Sciurus rubidiventris_.

_Color._--Upper parts and tail as in _Sciurus lutescens_. Cheeks
faintly washed with ochraceous-buff. Under parts and inner surface of
legs bright ochraceous-buff (distinctly more yellow than Ridgway's
pl. V, No. 10). Lateral stripes as in _S. lutescens_ (not distinctly
yellowish as in _S. seraiæ_), but black band usually less sprinkled
with gray. Scarcely a trace of gray in axillary region or on sides of
neck.

_Skull._--The skull in all respects closely resembles that of _S.
rubidiventris_ except that it is slightly smaller. Its large size and
the correspondingly large teeth readily distinguish it from that of
the South Natuna species.

_Measurements._--External measurements of type: total length 375;
head and body 195; tail vertebræ 180; hind foot 44 (41). Average and
extremes of nine specimens from the type locality; total length 363
(355-379); head and body 189 (171-196); tail vertebræ 170 (165-183);
hind foot 45 (44-46); hind foot without claws 42 (41-43).

_Specimens examined._--Ten (one in alcohol), all from the type
locality.

_Remarks._--Though suggesting two of the small South Natuna squirrels
in color, _Sciurus lautensis_ is obviously related to the dark
colored Bunguran form, with which it more nearly agrees in size.


SCIURUS NAVIGATOR (Bonhote).

    1894. _Sciurus prevostii_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 656. September, 1894 (Sirhassen).

    1901. _Sciurus prevostii navigator_ BONHOTE, Ann. and Mag. Nat.
    Hist., 7th ser., VII, p. 171. February, 1901 (Sirhassen).

Nine specimens, three from Sirhassen Island and six from Pulo Subi.

Those from Pulo Subi, while agreeing with the topotypes in color,
appear to average a trifle smaller, though the series is hardly
extensive enough to prove that this is constant.


RATUFA SIRHASSENENSIS (Bonhote).

    1894. _Sciurus bicolor albiceps_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 659. September, 1894 (Sirhassen).

    1900. _Ratufa ephippium sirhassenensis_ BONHOTE, Ann. and Mag.
    Nat. Hist., 7th ser., V, p. 498. June, 1900 (Sirhassen).

Two specimens, Sirhassen, June 8, 1900.

This species, though related to _Ratufa ephippium_, with which it
agrees in color-scheme, is sharply differentiated by its small size
and cranial peculiarities. It is in no way closely allied to _Ratufa
bunguranensis_ and _R. nanogigas_.

As compared with that of _Ratufa ephippium sandakanensis_ Bonhote,
the skull in addition to its small size (greatest length 57 instead
of 65) differs in general narrowness, in the relatively greater
breadth of the nasal branches of the premaxillaries, and in the form
of the audital bullæ. When the skull is held upside down and viewed
from behind the bullæ are seen to be narrower than in the Bornean
animal and to rise to a much greater height above the surface of the
basi-occipital.


RATUFA BUNGURANENSIS (Thomas and Hartert).

    1894. _Sciurus bicolor bunguranensis_ THOMAS and HARTERT,
    Novitates Zoologicæ, I, p. 658. September, 1894 (Bunguran).

    1895. _Sciurus bicolor bunguranensis_ THOMAS and HARTERT,
    Novitates Zoologicæ, II, p. 491. December, 1895 (Bunguran).

    1900. _Ratufa ephippium bunguranensis_ BONHOTE, Ann. and Mag.
    Nat. Hist., 7th ser., V, p. 497. June, 1900.

Thirteen specimens from Bunguran, all in various stages of the
change from the bleached winter coat to the summer pelage. In the
latter there is some color variation, mostly due to the greater or
less distinctness of the drab wash overlying the Prouts-brown or
'chocolate' of the upper parts. Not only does the drab vary in amount
in different individuals, but on every specimen it is more noticeable
when the animal is viewed from in front. The drab wash is of the same
character as that in _Ratufa affinis_, though less conspicuous.

As Mr. Thomas has pointed out to me, after examining a specimen
of the latter, _Ratufa bunguranensis_ is closely allied to _R.
pyrsonota_. Indeed its relationship to the Siamese species is much
closer than to the _R. ephippium_ of Borneo. Together with _R.
pyrsonota_ the Bunguran giant squirrel differs conspicuously from
that of Borneo in its narrow skull, lengthened audital bullæ, dark
feet, dark median line on under surface of tail, and entirely brown
back. From _R. pyrsonota_, however, it is readily separable by its
darker, less ochraceous color both above and below, drab washed back,
and by the much less distinct annulation of the hairs of the dorsal
surface.


RATUFA NANOGIGAS (Thomas and Hartert).

    1895. _Sciurus bicolor nanogigas_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 491. December, 1895 (Pulo Laut).

    1900. _Ratufa ephippium nanogigas_ BONHOTE, Ann. and Mag. Nat.
    Hist., 7th ser., V, p. 498. June, 1900 (Pulo Laut).

Four specimens, all from Pulo Laut, the type locality.

This strongly characterized dwarf species is allied to _Ratufa
pyrsonota_ and _R. bunguranensis_ with which it agrees in color
scheme. It is in no way closely related to the large Bornean _R.
ephippium_.


RATUFA ANGUSTICEPS sp. nov.

_Type._--Adult male (skin and skull) No. 104646 U. S. National
Museum. Collected on Pulo Lingung, off south coast of Bunguran, June
17, 1900. Original number 481.

_Characters._--Externally like _Ratufa anambæ_ and _R. melanopepla_.
Skull about equal to that of latter in length, but conspicuously
narrower.

_Color._--As the color is precisely like that of _Ratufa anambæ_ and
_R. melanopepla_ it requires no description.

_Skull and teeth._--The skull is immediately recognizable by its
general narrowness, but particularly in the region of the anterior
zygomatic roots. Ratio of lachrymal breadth to greatest length, 39.
In the other black backed species it is about 42. Audital bullæ
narrower and more elongate than in _R. melanopepla_, and more
elevated above level of basi-occipital (when skull is held upside
down). Lateral processes of basi-occipital obsolete.

Teeth as in the related species.

_Measurements._--External measurements of type: total length 748;
head and body 342; tail vertebræ 406; hind foot 79 (74).

Cranial measurements of type: greatest length 48.6 (70);[21] basal
length 57 (59); basilar length 52 (53); diastema 15.6 (16); length
of nasals 22 (23.4); breadth of nasals anteriorly 12 (13); breadth
of nasals posteriorly 6 (7); interorbital breadth 27 (28); lachrymal
breadth 28.4 (31); breadth between tips of postorbital processes 38
(41); zygomatic breadth 41 (44); mastoid breadth 31 (32.6); mandible
40 (41.6); maxillary toothrow (alveoli) 14 (14); mandibular toothrow
(alveoli) 14.6 (14.4).

_Specimens examined._--One, the type.

_Remarks._--While this squirrel exactly resembles the other black
backed species with untufted ears, so far as external characters
are concerned, it seems to be well differentiated in cranial
peculiarities. No black backed _Ratufa_ has hitherto been recorded
from the Natunas.


RHINOSCIURUS sp.

An immature long-nosed squirrel was taken on Sirhassen Island, June
4, 1900. In the absence of material for comparison I am unable to
determine the species. The genus is new to the islands.


ARCTOGALIDIA INORNATA sp. nov.

_Type._--Adult[22] male (skin and skull) No. 104859 U. S. National
Museum. Collected on Bunguran Island, North Natunas, June 23, 1900.
Original number 502.

_Characters._--Much smaller than _Arctogalidia leucotis_ from the
Malay Peninsula or _A. stigmatica_ from Borneo (greatest length of
skull about 100 instead of 115) and in color paler than either, the
dark dorsal stripes obsolete in adult.

_Color._--General color of back and sides light silvery gray
irregularly suffused with buff and slightly darkened by blackish
hair-tips and by appearance at surface of hair-brown basal portion of
fur. The buff suffusion is least noticeable on back, slightly more
apparent on sides and flanks, and most evident on sides of neck,
where it usually brightens almost to buff-yellow in distinct contrast
with surrounding parts. On middle of back there is a trace of the
middle dark stripe of the three normally present in members of the
genus. Head essentially like back though somewhat more gray. Muzzle
and ill-defined eye ring blackish. Cheeks and short median stripe on
forehead dull whitish gray. Under parts essentially like back, but
buff tinge more diffuse. Feet and ears dark brown. Tail like back but
darkening to uniform brown beyond middle.

Newly born young are clear bluish gray, with scarcely a tinge of
buff. The three black dorsal stripes are clearly defined and normal
in extent.

_Skull._--In addition to its smaller size the skull differs from
that of the Bornean _Arctogalidia stigmatica_ in the relatively
larger braincase, and less prominent audital bullæ. The braincase
is nearly as broad as in the Bornean species, but the zygomatic
width is distinctly less. Audital bullæ less raised above level
of basi-occipital when skull is held upside down and viewed from
behind. The sagittal crest, though of normal development in very
old individuals, is absent at an age when it is well grown in the
larger species. In _Arctogalidia leucotis_ and _A. stigmatica_, even
in animals so young that the teeth are unworn and all the sutures
of the rostrum plainly visible, the sagittal crest is a knife-like
ridge extending from proencephalon to lambdoid suture, and rising
to a height of about 4 mm. over middle of braincase. In much older
individuals of _A. inornata_, with worn teeth and nearly obliterated
rostral sutures, the crest is represented by a low ridge about 5
mm. wide over middle of braincase and flat or grooved on top. At
this stage it rises very inconspicuously above level of the adjacent
surface, from which it is distinguished more by the texture of the
bone than by actual form.

_Teeth._--The teeth are uniformly much smaller than in _Arctogalidia
leucotis_ and _A. stigmatica_, but I can detect no important
differences in form.

_Measurements._--External measurements of type: total length 1027;
head and body 469; tail vertebræ 558; hind foot 78 (73.) External
measurements of an adult female: total length 911; head and body 431;
tail vertebræ 480; hind foot 77 (72).

Cranial measurements of type: greatest length 102 (115);[23] basal
length 96 (106); basilar length 92 (103); median palatal length 53
(60); palatal breadth between anterior molars 13 (15.4); zygomatic
breadth 55 (60); breadth between tips of postorbital processes
41 (39); constriction in front of postorbital processes 19 (18);
constriction behind postorbital processes 13 (12); breadth of
braincase above roots of zygomata 32 (33); mastoid breadth 36 (38);
mandible 76 (86); maxillary toothrow (exclusive of incisors) 34[24]
(41); mandibular toothrow (exclusive of incisors) 39 (44); crown of
first upper molar 5.4 × 5 (5.4 × 5.6); crown of second upper molar 4
× 5 (5.4 × 6.4); crown of second lower molar 7 × 4.2 (8.4 × 5.4).

_Specimens examined._--Seven (two young in alcohol and one skull
without skin), all from the type locality.

_Remarks._--_Arctogalidia inornata_ is so distinct from the
previously described species as to require no special comparisons. It
is common on Bunguran where it frequents the cocoanut trees, living
for the most part in the tops among the leaf stalks.


VIVERRA TANGALUNGA Gray.

    1895. _Viverra tangalunga_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 490. December, 1895 (Bunguran).

Nine specimens from Bunguran. These agree in all respects with the
Bornean animal.


TUPAIA SPLENDIDULA Gray.

    1894. _Tupaia splendidula_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 656. September, 1894 (Bunguran).

    1893. _Tupaia splendidula typica_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 489. December, 1895 (Bunguran).

Two specimens from Bunguran.


TUPAIA LUCIDA (Thomas and Hartert).

    1895. _Tupaia splendidula lucida_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 490. December, 1895 (Pulo Laut).

Seven specimens (two in alcohol) from Pulo Laut.


TUPAIA SIRHASSENENSIS sp. nov.

    1894. _Tupaia tana_ THOMAS and HARTERT, Novitates Zoologicæ, I,
    p. 657. September, 1894 (Sirhassen).

_Type._--Adult male (skin and skull) No. 104712 U. S. National
Museum. Collected on Sirhassen Island, South Natunas, June 5, 1900.
Original number 442.

_Characters._--In general similar to Bornean specimens of _Tupaia
tana_, but smaller (hind foot 47 instead of 52, greatest length of
skull 55 instead of 60), gray markings on head and shoulders less
distinct, and red of tail brighter. Rostral portion of skull less
attenuate than in _Tupaia tana_.

_Color._--The color so exactly resembles that of the common Bornean
_Tupaia tana_ as to need no detailed description. Gray of head
darker than in the Bornean animal and light shoulder markings less
distinct and sharply defined. Under side of tail light orange-rufous,
darkening to ferruginous toward edge. (In _T. tana_ these colors are
replaced by dull ferruginous and hazel respectively.)

_Skull and teeth._--The skull is throughout much smaller than in
specimens of _Tupaia tana_ from Borneo. In form it differs from that
of _T. tana_ in less slender and elongate rostrum, narrower braincase
and slightly shorter audital bullæ. Suborbital vacuity much broader
than in _T. tana_. Teeth as in the Bornean animal.

_Measurements._--External measurements of type: Total length 355;
head and body 203; tail vertebræ 152; hind foot 46.4 (44). Average
and extremes of four adults from the type locality: total length 367
(365-371); head and body 203; tail vertebræ 163 (162-168); hind foot
45.4 (44-46.6); hind foot without claws 42.5 (41-44).

Cranial measurements of type: greatest length 54.6 (61);[25] basal
length 49 (54); basilar length 46.4 (51); median palatal length 48
(53); distance from lachrymal notch to tip of premaxillary 27.6 (31);
least interorbital breadth 14.4 (16); zygomatic breadth 25 (28.4);
mandible 38 (41); maxillary toothrow (behind diastema) 20 (21.4);
mandibular toothrow (behind diastema) 17 (18).

_Specimens examined._--Five, all from the type locality.


GALEOPITHECUS VOLANS (Linnæus).

    1894. _Galeopithecus volans_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 657. September, 1894 (Bunguran and Sirhassen).

Two specimens from Sirhassen and two (one young in alcohol), from
Bunguran. Also foetus of one of the Sirhassen specimens.


EMBALLONURA ANAMBENSIS Miller.

Four specimens from Bunguran. These agree essentially with the Anamba
animal, but show some slight cranial peculiarities.


PIPISTRELLUS SUBULIDENS sp. nov.

_Type._--Adult female (in alcohol) No. 104758 U. S. National Museum.
Collected on Sirhassen Island, South Natunas, June 3, 1900.

_Characters._--Similar to _Pipistrellus pipistrellus_ (Schreber) in
size, color and external form, but skull with broader rostrum, and
inner upper incisor without supplemental cusp.

_Skull._--The skull is of the same size as that of _Pipistrellus
pipistrellus_, but the braincase is narrower and more elongate, and
the rostrum is very markedly shorter and broader. The great breadth
of the anterior portion of the skull involves also the palate and
interpterygoid space, both of which are noticeably wider than in
_Pipistrellus pipistrellus_. Audital bullæ slightly smaller than in
the European species.

_Teeth._--The teeth are essentially as in _Pipistrellus
pipistrellus_, except that the inner upper incisor lacks the
small supplemental cusp. Mandibular teeth wider than those of _P.
pipistrellus_.

_Measurements._--External measurements of type: total length 76; head
and body 41; tail 33; tibia 14; foot 6; calcar 10; forearm 32.4;
thumb 6; second digit 30; third digit 60; fourth digit 53; fifth
digit 43; ear from meatus 11; ear from crown 9; width of ear 9.6;
tragus (measured in front) 4.

Cranial measurements of type: greatest length 12.4 (12);[26] basal
length 11.8 (11.6); basilar length 9 (9); zygomatic breadth 8.4 (8);
least interorbital breadth 3.2 (3.2); greatest length of braincase
8 (7.6); greatest breadth of braincase above roots of zygomata 6.6
(6.6); mandible 8.8 (8.4); maxillary toothrow (exclusive of incisors)
4.2 (4.2); mandibular toothrow (exclusive of incisors) 4.8 (4.8).

_Specimens examined._--Six (in alcohol), all from the type locality.

_Remarks._--I am unable to identify this bat with any described
species. Externally it is practically identical with _Pipistrellus
pipistrellus_ except that the color, so far as can be judged from
specimens preserved in alcohol, is more blackish. Internally it is
readily distinguished by the characters of the skull and teeth.
From _Pipistrellus abramus_ it differs externally in smaller size,
narrower ears, and in the absence of any unusual development of the
penis. The incisors differ from those of _P. abramus_ in the same
manner as from those of _P. pipistrellus_.


HIPPOSIDEROS LARVATUS (Horsfield).

Two specimens (one in alcohol) were collected on Sirhassen Island,
June 6 and 7, 1900.


RHINOLOPHUS AFFINIS (Horsfield).

One badly damaged specimen from Bunguran appears to be referable to
typical _Rhinolophus affinis_. The forearm cannot be measured, but
the third finger is 75 mm. in length. Tibia 21, foot 10.4, ear from
meatus 21. Ridge on muzzle beneath edge of nose leaf low, broad and
hairy, not in the least suggesting a supplementary leaflet.


RHINOLOPHUS SPADIX sp. nov.

    1894. _Rhinolophus affinis_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 656. December, 1895 (Sirhassen).

_Type._--Adult female (in alcohol) No. 104752 U. S. National Museum.
Collected on Sirhassen Island, South Natunas, June, 1900.

_Characters._--In general like _Rhinolophus affinis_ but much
smaller. Color uniform tawny brown. Muzzle with distinct supplemental
leaflets.

_Muzzle._--Muzzle and noseleaf precisely as in _Rhinolophus
affinis_, except that the ridge on muzzle beneath edge of horseshoe
is developed into a distinct supplemental leaflet resembling those
present in _Hipposideros_. In this respect _Rhinolophus spadix_
resembles the animal from Burmah referred by Thomas to _Rhinolophus
rouxii_;[27] but the terminal erect portion of the noseleaf is not
shortened or in any way peculiar in form.

_Ears._--The ears resemble those of _Rhinolophus affinis_, except
that they are not as large.

_Color._--Fur everywhere russet, slightly paler on ventral surface,
darker and somewhat tinged with hazel above. Ears and membranes dark
brown.

_Skull and teeth._--The skull and teeth exactly resemble those
of mainland specimens of _Rhinolophus affinis_ except for their
uniformly smaller size.

_Measurements._--External measurements of type: total length, 70
(85[28]); tail 21 (23); tibia 17.6 (24); foot 8 (10); calcar 12 (13);
forearm 43 (51); thumb 8 (8.6); second digit 32 (40); third digit 64
(77); fourth digit 53 (61); fifth digit 54 (63); ear from meatus 17
(20); ear from crown 14 (17); length of noseleaf from lip 13 (16);
greatest width of noseleaf 8 (9).

Cranial measurements of type: greatest length 18 (23); basal length
16 (20.4); basilar length 14.6 (18); zygomatic breadth 9 (11); least
interorbital breadth 2.4 (2.4); greatest length of braincase 10.4
(13); greatest breadth of braincase above roots of zygomata 8 (9.4);
frontopalatal depth (at middle of molar series) 4 (4.8); depth of
braincase 6 (7); mandible 11.8 (15); maxillary toothrow (exclusive
of incisor) 6.8 (9); mandibular toothrow (exclusive of incisors) 7
(9.8).

_Specimens examined._--Three (one skin), all from the type locality.

_Remarks._--_Rhinolophus spadix_ is so readily distinguished from
its relatives of the _R. affinis_ group that it needs no special
comparisons. It is a much smaller animal than the species from the
Anambas that I recently referred to _R. rouxii_.[29] In color the
latter is a dull brown not in the least resembling the russet of _R.
spadix_.


CYNOPTERUS MONTANOI Robin.

    1894. _Cynopterus marginatus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 655. September, 1894 (Sirhassen and Bunguran).

    1899. _Cynopterus montanoi_ MATSCHIE, Die Fledermäuse des
    Berliner Museums für Naturkunde, p. 75. August, 1899. (Natuna
    record of _C. marginatus_ placed in synonymy of _C. montanoi_.)

Five specimens (three skins) from Sirhassen. These agree so closely
with a skin and two bleached alcoholic specimens from Singapore,
which I suppose to be the same as the Malaccan _Cynopterus montanoi_,
that without more material it is impossible to distinguish the Natuna
animal from that of the southern extremity of the Malay Peninsula.
_Cynopterus montanoi_ as thus understood differs from _C. angulatus_
Miller[30] of Lower Siam in its more slender skull and in the
absence of the white border of the ear, and from _C. titthæcheilus_
(Temminck) of Sumatra and Java in its conspicuously smaller size.


PTEROPUS VAMPYRUS (Linnæus).

    1894. _Pteropus vampyrus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 655. September, 1894 (Bunguran).

    1895. _Pteropus vampyrus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 489. December, 1895 (Bunguran).

Six skins from Bunguran.


? PTEROPUS HYPOMELANUS Temminck.

    1894. _Pteropus hypomelanus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 655. September, 1894 (Sirhassen).

    1895. _Pteropus hypomelanus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 489. December, 1895 (Pulo Pandak, Pulo
    Panjang and Pulo Laut).

Eight (one in alcohol) from Sirhassen and seven (one in alcohol) Pulo
Laut. It is highly probable that these specimens represent a species
distinct from the true _Pteropus hypomelanus_ of Ternate.


NYCTICEBUS TARDIGRADUS (Linnæus).

    1894. _Nycticebus tardigradus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 655. September, 1894 (Bunguran).

    1895. _Nycticebus tardigradus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 489 (Bunguran).

One specimen from Bunguran.


MACACUS 'CYNOMOLGUS' Auct.

    1894. _Macacus cynomolgus_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 654. September, 1894 (Bunguran).

    1895. _Macacus cynomolgus_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 489. December, 1895 (Bunguran).

A specimen from each of the following islands: Sirhassen, Pulo
Lingung and Pulo Laut.


SEMNOPITHECUS CRISTATUS (Raffles).

Two monkeys from Sirhassen appear to be referable to this species.


SEMNOPITHECUS NATUNÆ Thomas and Hartert.

    1894. _Semnopithecus natunæ_ THOMAS and HARTERT, Novitates
    Zoologicæ, I, p. 652. September, 1894 (Bunguran).

    1895. _Semnopithecus natunæ_ THOMAS and HARTERT, Novitates
    Zoologicæ, II, p. 489. (Bunguran.)

Ten specimens from Bunguran.


FOOTNOTES:

[1] For location of the Natuna Islands see Proc. Washington Acad.
Sci., II, p. 204. August 20, 1900.

[2] Thomas (O.) and Hartert (E.). List of the first collection of
mammals from the Natuna Islands. Novitates Zoologicæ, I, pp. 652-660.
September, 1894.

Thomas (O.). Revised determinations of three of the Natuna rodents.
Novitates Zoologicæ, II, pp. 26-28. February, 1895.

Thomas (O.) and Hartert (E.). On a second collection of mammals from
the Natuna Islands. Novitates Zoologicæ, II, pp. 489-492. December,
1895.

Bonhote (J. Lewis). On the squirrels of the Ratufa (Sciurus) bicolor
group. Ann. and Mag. Nat. Hist., 7th ser., V, pp. 490-499. June, 1900.

Thomas (O.). The red flying squirrel of the Natuna Islands. Novitates
Zoologicæ, VII, p. 592. December 8, 1900.

Bonhote (J. Lewis). On the Squirrels of the Sciurus Prevostii Group.
Ann. and Mag. Nat. Hist., 7th ser., VII, pp. 167-177. February, 1901.

[3] Gray's "Notice of a species of Tupaia from Borneo, in the
collection of the British Museum" in the Proceedings of the
Zoological Society of London for 1865 (p. 322) may be added to the
bibliography of Natuna mammals, as the animal described, though
supposed to have been taken in Borneo, is apparently confined to
Bunguran Island, the largest of the Natunas.

[4] _Megaderma spasma_, _Myotis muricola_, _Taphozous melanopogon_,
_Mydaus meliceps_, _Paradoxurus hermaphroditus_, _Lutra sumatrana_
and _Mus ephippium_.

[5] See papers already cited, also Novitates Zoologicæ, I, p. 468
(letter from Mr. Everett); _ibid._, I, p. 483 (note on land shells
by Mr. E. Smith), _ibid._, II, p. 478 (Birds); _ibid._, II, p. 499
(Reptiles).

[6] Sitz.-Berich. der Gesellsch. Naturforschender Freunde zu Berlin,
1893, p. 224.

[7] For the opportunity of examining the skull of an adult male
from Balabac I am indebted to the courtesy of Mr. D. G. Elliot. A
photograph (slightly reduced) of this specimen was published by Mr.
Elliot in 1896 (Field Columbian Museum, Publication II, Zoological
Series, I, No. 3, pl. XI, May, 1896).

[8] Measurements in parentheses are those of an adult male topotype
of _Tragulus nigricans_.

[9] Measurements in parentheses are those of a less mature specimen
from Bunguran.

[10] Measurements in parentheses are those of a Tenasserim specimen
(female) of _Sus cristatus_ so young that the posterior molar is not
fully in place.

[11] Last molar not fully grown.

[12] See Proc. Biol. Soc. Washington, XIII, pl. III and IV.

[13] Collector's measurement.

[14] Measurements in parentheses are those of the type of _Mus
validus_.

[15] In the type of _Mus mülleri_ the diastema is 12 mm.

[16] Ann. and Mag. Nat. Hist., 6th ser., XIV, p. 450. December, 1894.

[17] Measurements in parentheses are those of an adult male topotype
of _Sciurus tenuis_.

[18] Measurements in parentheses are those of an older specimen of
_Sciurus natunensis_ from Sirhassen.

[19] Measurements in parentheses are those of an adult _Sciurus
notatus_ from Borneo.

[20] Measurements in parentheses are those of an adult Bornean
_Sciurus notatus_.

[21] Measurements in parentheses are those of the type of _Ratufa
melanopepla_.

[22] Teeth very much worn and many of them absent.

[23] Measurements in parentheses are those of a young adult _A.
stigmatica_ from British North Borneo.

[24] Tooth measurements are from a younger specimen (male) with
perfect dentition.

[25] Measurements in parentheses are those of an adult male Bornean
_Tupaia tana_.

[26] Measurements in parentheses are those of an adult skull of
_Pipistrellus pipistrellus_ from Switzerland.

[27] Ann. Mus. Civ. di Storia Nat. di Genova, Ser. 2, X, p. 923, pl.
XI, 1892.

[28] Measurements in parentheses are those of an adult female
_Rhinolophus affinis_ from Trong, Lower Siam.

[29] Proc. Washington Acad. Sci., II, p. 234. August 20, 1900.

[30] Proc. Acad. Nat. Sci. Philadelphia, 1898, p. 316. July, 1898.


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Transcriber's Note:

Obvious typographical errors have been repaired.

_Underscores_ surround italicized content.