1460 



CLASS MAMMALIA. 



the Pterofiodidee, or Fruit-bats, and is unknown in a fossil condition. 

 In the latter, which comprises all other Bats, the teeth are covered 

 with minute pointed cusps ; nearly all the species being of com- 

 paratively small size. The most remarkable feature presented in 

 the past history of this order is the occurrence of forms closely 



Fig. 1344. — Skeleton of the Mouse-coloured Bat (Vespertilio murinus). a, Humerus ; b, 

 Scapula ; d, Radius, with the rudimentary ulna at its proximal end ; e, Carpus ', /, Pollex ; g g, 

 Metacarpals ; s s, Sternum ; p, Pelvis ; i, Supplementary bone attached to the calcaneum. 



allied to those of the present day as low down as the Bridger 

 Eocene of North America, which indicates that the characteristic 

 features of the order were probably acquired at a period not 

 later than the Lower Eocene or Cretaceous epoch. The following 

 families of Microchiroptera may be noticed : — 



