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[Author's Edition, extracted from Bulletin of the American Museum of
Natural History, Vol. IX, September 28, 1897.]


ARTICLE XIX.--DESCRIPTION OF A NEW VESPERTILIONINE BAT FROM YUCATAN.


By J.A. ALLEN.


In a small collection of mammals recently sent by Dr. G.F. Gaumer from
Izamal, Yucatan, to this Museum for identification, is a single
specimen of a species of _Adelonycteris_, which appears to be
undescribed. It may be called

ADELONYCTERIS GAUMERI, sp. nov.

     Above dark brown, with an olivaceous wash, the fur being
     uniform dark brown to the base tipped with a slight tinge of
     olivaceous, the extreme tip slightly grayish in certain
     lights; below much lighter, the fur being dark brown basally
     and broadly tipped with pale buffy gray; ears and membranes
     black, naked, and with no trace of a whitish border. Ears of
     medium size, rather thin, evenly convex on the front border,
     slightly hollowed on the posterior border below the rounded
     posteriorly directed tip; tragus long and rather narrow,
     pointed, equal to half the height of the ear. Face
     semi-nude, about as in _A. fusca_.

     _Measurements._--"Length, 95 mm.; expanse, 286; wing, 124;
     tail, 40";[1] ear, 21; tragus, 11; fore arm, 39; thumb, 7;
     3d digit, 79 = phal. i, 37, phal. ii, 24; phal. iii, 11;
     phal. iv, 7; tibia, 70; foot, 8.

     [Footnote 1: Collector's measurements from the fresh
     specimen; the rest are from the dry skin.]

     _Skull._--Similar in a general way to that of _A. fusca_,
     but about one-half smaller. Middle inner upper incisors
     considerably worn, and the ridges for muscular attachment
     strongly developed, indicating an old individual. Greatest
     length (front base of incisors to end of crest), 18; mastoid
     breadth, 8.3; zygomatic breadth, 10.1; interorbital breadth,
     4; length of molar-premolar series, 4.2; palatal length,
     5.3.

     _Type_, No. 12753/11040, [female symbol] ad., Izamal,
     Yucatan; collected by Dr. George F. Gaumer, for whom the
     species is named.

In coloration _Adelonycteris gaumeri_ resembles examples of _A. fusca_
in immature dark pelage, but it differs from this species in the
thinness of the ears, and in the greater relative length of the
narrower and more tapering tragus, and in its very much smaller size.
In size it resembles both _'Vesperugo' propinquus_ Peters and _V.
(Marsipolæmus) albigularis_ Peters, respectively from Guatemala and
Mexico. The peculiar structure of the ears, to say nothing of the
coloration, in _V. albigularis_, render comparison with this species
unnecessary. _V. propinquus_ is described as reddish above, paler and
more reddish yellow below, and in this respect is widely different
from _A. gaumeri_. It has also a longer thumb and foot than _A.
gaumeri_.

The type and only specimen of this species has been kindly presented
by Dr. Gaumer to this Museum, with other specimens of Yucatan mammals.