196 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 
peatinse; the presternum small, with forward-projecting, variously 
developed median lobe, the mesosternum flat and scarcely keeled, 
usually slender; foot normal; fibula thread-like, complete or with 
upper extremity cartilaginous, extending to head of tibia; pelvis 
normal, the boundaries of the sacral vertebrse distinct, the ischia widely 
separated posteriorly, a symphysis pubis in males; lumbar vertebrae 
free ; skull without postorbital processes ; premaxillaries without 
palatal branches, the palate widely emarginate anteriorly ; palate ab- 
ruptly narrowed behind toothrows, the sides of its posterior exten- 
sion parallel or nearly so; teeth usually normal, though in a few 
genera showing a tendency to reduction of the cusps; ears usually 
though not invariably separate, the anterior border with distinct 
basal lobe (except in Tomopeatinse) ; tragus usually well developed, 
simple ; muzzle without distinct leaf-like outgrowths ; tail well devel- 
oped, extending to edge of wide interfemoral membrane. 
History .- — The family Vespertilionidse, with its almost universal 
distribution, and containing, as it does, the best known and most 
familiar species, has been very generally recognized in approximately 
the sense in which it is now understood. Certain genera formerty 
placed with it have been recently removed, but, on the tvhole, the 
group has been more uniformly treated than any other family except, 
perhaps, the fruit bats. 
Remarks . — -The members of this family are recognizable exter- 
nally by their simple muzzles and lips, usually separate ears with 
well-developed, straight, or slightly curved tragi, long tails extend- 
ing to edge of wide interfemoral membrane, but never much beyond ; 
presence of only two bony phalanges in third finger, and absence of 
sucking disks on sole and thumb. Internally they are distinguished 
by the highly developed double articulation between scapula and 
humerus, the very rudimentary ulna, the essentially unmodified 
shoulder girdle and pelvis, the conspicuous anterior emargination of 
the bony palate, and the essentially normal teeth. 
A very high position for the Vespertilionidse is indicated by the 
structure of the wing, in which the family stands further removed 
from the Pteropidse and from nonvolant mammals than any other 
group except the Molossidse and Mystocopidse. In the extreme re- 
duction of the ulna it even surpasses both of these. 
Principal subdivisions . — The known genera of Vespertilionidse 
represent at least six subfamilies. 
KEY TO THE SUBFAMILIES OF VESPERTILIONHLE. 
Anterior upper premolar (pm 2 ) large, not differing conspicuously from 
posterior premolar (pm 4 ) in size or form; nostrils tubularly elongated 
Murinin^e, p. 229. 
Anterior upper premolars (pm 2 and pm 3 ) greatly reduced in size or absent; 
when present conspicuously different from posterior premolar (pm 4 ) in 
both size and form ; nostrils not tubularly elongated. 
