THE FAMILIES AND GENERA OF BATS. 
199 
Upper premolars 1-1. 
Upper incisors 2-2. 
Ears noticeably enlarged. 
Audital bullae as wide as space between them, 
Lcephotis, p. 215. 
Audital bullae much wider than space between them, 
Histiotus, p. 214. 
Ears not noticeably enlarged. 
Depth of bra incase, including audital bullae, about equal 
to distance from incisors to posterior root of zygoma, 
Glauconycteris , p. 221. 
Depth of braincase, including audital bullae, much less 
than distance from incisors to posterior root of zygoma. 
Skull noticeably flattened, the occipital depth less 
than one-third greatest length. 
Rostrum broad ; lachrymal region so inflated as 
to be distinctly visible when skull is viewed 
from below Mimetillus, p. 213. 
Rostrum normal ; lachrymal region quite hidden 
when skull is viewed from below, 
Tylonycteris, p. 212. 
Skull not noticeably flattened, the occipital depth more 
than one-third greatest length. 
Upper canine with distinct supplemental cusp at 
posterior base of shaft Pliiletor, p. 213. 
Upper canine without supplemental cusp at pos- 
terior base of shaft. 
Outer upper incisor large, crowded inward 
between inner incisor and canine, 
Hesperoptenus, p. 211. 
Outer upper incisor small, on outer side of 
inner incisor and widely separated from 
canine. 
Surface of forearm, ta\l, and legs thickly 
sprinkled with small, pointed, horny 
outgrowths ; upper toothrow strongly 
concave on inner side anteriorly, 
Rliinopterus, p. 210. 
Surface of forearm, tail, and legs smooth ; 
upper toothrow slightly concave on in- 
ner side anteriorly. 
Rostrum evenly convex laterally ; 
nares not extending half way to 
interorbital constriction ; palatal 
emargination deeper than broad, 
Eptesicus , p. 207. 
Rostrum noticeably concave on each 
side of middle line ; nares extend- 
ing about half way to interorbital 
constriction ; palatal emargination 
broader than deep, 
Vespertilio, p. 209. 
