THE FAMILIES AND GENERA OF BATS. 157 
Characters . — Like V ampyressa , but with lower incisors only 1-1, 
and surface sculpture on molars obsolete. Dental formula : 
- 2 3. 1. - - 3 4 5 6- 
1 - -.1. -2 - 4 5 6 - 
. 2-2 1-1 2-2 2-2 oa 
^v c x^v pm ^r m =^ =2b - 
2-2 
Species examined. — Vampyriscus bidens (Dobson). 
Remarks. — Vampyriscus , like V ampyressa and V ampyrodes, seems 
too distinct from V ampyr ops to be united with it as a subgenus. 
This is the most divergent of the three, having lost two of its lower 
incisors, and agreeing with V ampyressa in the reduced number of 
molars and in the simplified structure of m 2 and m x . 
Genus CHIRODERMA Peters. 
1860. Gliiroderma Peters, Monatsber. k. preuss. Akad. Wissensch., Berlin, 
p. 747. 
1866. Mimetops Gray, Proe. Zool. Soc. London, p. 117 (cited as MS. syn- 
onym of Ghiroderma ) . 
1878. Gliiroderma Dorson, Catal. Ckiropt. Brit. Mus., p. 531. 
Type-species. — Ghiroderma villosum Peters. 
Geographic distribution . — Tropical America, north to Costa Rica. 
Number of forms . — Four species of Ghiroderma are now known. 
Characters . — Dental formula: 
-2 3. 1. - -3456 - .2-2 „ 1 - 1 _ 2-2 
1 2 -. 1. - 2 - 4 5 6 - % 2 - 2’ C 1 - 1’ pm 2-2’ 
2 _- 
2 - 
Teeth in general similar to those of V ampyr ops, but inner upper 
incisors more slender and slightly less oblique; lower incisors not as 
closely crowded ; anterior premolar both above and below smaller and 
not in contact with posterior premolar, each with diameter of crown 
decidedly less than that of its respective canine, that of lower jaw 
with crown area scarcely more than four times that of a lower incisor 
and with cusp reduced or obsolete; upper molars with the cusps, 
notably the protocone, the base of which in m 2 is nearly terete, much 
thickened, so as to encroach on crushing area of crown, the surface of 
which is marked by a few coarse wrinkles; outer cusps with cingula 
obsolete or absent ; lower molars with outer cusps similarly thickened 
as compared with those of V ampyr ops, this particularly the case with 
the hypoconid, which, in both teeth, is distinctly subterete; inner 
cusps oi m t practically absent, the tooth thus differing notably 
from that of V ampyr ops, those of m 2 , however, thickened and well 
developed, a supplemental cusp, probably homologous with that some- 
times present in Artibeus, between metaconid and entoconid, and 
nearly as large as the latter. Skull essentially like that of Vam- 
pyrops but with nasal bones apparently absent, their place occupied 
by an emargination extending back from nares to between orbits.® 
° I have seen no skulls sufficiently immature to show whether the nasals are 
completely absent or not. 
