158 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 
Mandible with angular process remarkably short and ill defined. In 
external characters not essentially different from V ampyr ops. 
Species examined. — Chiroderma salvini Dobson, C. jesupi J. A. 
Allen, C. dorice Thomas, and C. villosum Peters. 
Remarks. — Although not distantly related to Vampyrops this genus 
is readily distinguishable by the apparent absence of the nasals, the 
different tooth formula, the reduced condition of pm 3 and pm 3 , and 
the peculiar thickening of the cusps of the molars. 
Genus MESOPHYLLA Thomas. 
1901. Mesophylla Thomas, Ann. and Mag. Nat. Hist., 7th ser., VIII, p. 143. 
August, 1901. 
Type-species. — Mesophylla macconelli Thomas. 
Geographic distribution. — British Guiana. 
Number of forms. — Only the type species is known. 
Characters — Dental formula : 
-2 3 . 1 . — 3456 -^ 2-2 1-1 
1 2 . 1 . - 2 - 45672 - 2’ 6 1-1 
2 — 2 
V m 9 — m 
A — A 
2 - 
3 - 
Upper incisors small but strongly contrasted in size, separated from 
each other and from canines by distinct spaces, the inner pair con- 
verging terminally, their cutting edge entire. Lower incisors small, 
subequal, forming a continuous, nearly straight line between canines. 
Canines slender and very sharply pointed, the upper long at base and 
with well-developed cingulum, the lower with base somewhat pro- 
duced backward. Upper premolars acutely pointed, with distinct 
cutting edges and well-developed concave inner surface. Lower pre- 
molars approximately like lower canine in form, though smaller, 
each with a single main anterior cusp and a distinct, flat, posterior 
heel ; pm 3 in contact with canine ; pm 4 spaced both anteriorly and pos- 
teriorly. First upper molar much smaller than second, its crown 
triangular in outline, with barely indicated protocone and high para- 
cone. Second upper molar with the crown basin-shaped and nearly 
smooth, its single cusp, probably the paracone, well developed and 
situated antero-externally. First lower molar resembling last pre- 
molar, its crown mostly flat, but with a single high cusp anteriorly. 
Second lower molar rather longer than first, its outline narrowly oval 
with narrow end forward, its width scarcely greater than that of 
mandibular ramus. The surface is basin-shaped, smooth, and the 
edges bear two distinct cusps on inner side of tooth and one at middle 
of front. Last lower molar very small, showing no definite structure, 
its size about equal to that of a lower incisor. Skull much as in 
Vampyrops, but with relatively smaller rostrum narrowing more 
noticeably in front. Nasal region depressed. Basisphenoid pits 
shallow and ill defined. Ears and noseleaf showing no marked pecul- 
