THE FAMILIES AND GENERA OP BATS. 157 



Characters. — Like Vampyressa, but with lower incisors only 1 - 1 , 

 and surface sculpture on molars obsolete. Dental formula : 



- 2 3. 1. -- 3 4 5 6- .2-2 1-1 2-2 2-2 oc 



' 1-- 1. -2-4 5 6- l lTT' C r^ m 2^2' m 2^2= 26 - 



Species examined. — Vampyriscus bidens (Dobson). 



Remarks. — Vampyriscus, like V ampyressa and Vampyrodes, seems 

 too distinct from Vampyrops 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 Vampyressa in the reduced number of 

 molars and in the simplified structure of m z and m x . 



Genus CHIRODERMA Peters. 



1860. Chiroderma Petees, Monatsber. k. preuss. Akad. Wissensch., Berlin, 

 p. 747. 



1866. Mimetops Gray, Proe. Zool. Soc. London, p. 117 (cited as MS. syn- 

 onym of Chiroderma). 



1878. Chiroderma Douson, Catal. Chiropt. Brit. Mus., p. 531. 



Type-species. — Chiroderma villosum Peters. 



Geographic distribution. — Tropical America, north to Costa Rica. 

 Number of forms. — Four species of Chiroderma are now known. 

 Characters. — Dental formula : 



-2 3. 1. --3456-. 2-2 1-1 2-2 2 - 2_ OQ 



12-.1.-2-456- l 2^2' ° T=V i ""' 2^2' M 2^~^ 

 Teeth in general similar to those of Vampyrops, 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 Vampyrops, this particularly the case with 

 the hypoconid, which, in both teeth, is distinctly subterete; inner 

 cusps of t»i practically absent, the tooth thus differing notably 

 from that of Vampyrops, 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. 



