196 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 



peatinae; 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 vertebrae 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 Tomopeatinae) ; 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 Vespertilionidas, 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 formerly- 

 placed with it have been recently removed, but, on the whole, 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 Vespertilionidaa is indicated by the 

 structure of the wing, in which the family stands further removed 

 from the Pteropidae and from nonvolant mammals than any other 

 group except the Molossidae and Mystocopidae. In the> extreme re- 

 duction of the ulna it even surpasses both of these. 



Principal subdivisions. — The known genera of Vespertilionidae 

 represent at least six subfamilies. 



KEY TO THE SUBFAMILIES OF VESPERTILIONIDAE. 



Anterior upper premolar (jim 1 ) large, not differing conspicuously from 

 posterior premolar (pm 4 ) in size or form; nostrils tubularly elongated 



Murinin^;. 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. 



