Order CHIROPTERA. 



BATS. 



The order is divided into two suborders: the Megachiroptera or 

 Fruit-eating Bats, containing the Old World family FleropodidcB, or so- 

 called Flying Foxes; and the Microchiroptera, which includes the rest 

 of the Bats and is the only one represented in North America. 



Bats are flying mammals, being supplied with a leathery membrane 

 supported by enormously elongated fingers and attached to the hind 



legs and sides of the body, which serves 

 as a wing. In addition to the four elong- 

 ated fingers supporting the wing mem- 

 brane, there is a detached thumb or pollex, 

 which projects from the upper margin 

 and is provided with a hooked claw. 

 From the inner side of the ankle joint 

 projects a cartilaginous process called 

 the calcar, which supports a portion of 

 the membrane joining the legs and tail 

 known as the interfemoral membrane. 

 Another noticeable character in Bats 

 belonging to the suborder Microchirop- 

 tera is the highly developed tragus, a 

 process arising within the conch of the 

 ear, which varies in shape and size in many species, and is often of 

 diagnostic value. Noticeable peculiarities in the myology of these 

 animals are found in the presence oi a muscle, known as the occipito- 

 pollicalis, extending from the occipital bone to the terminal phalanx of 

 the pollex and in the divided sections of the platysma. Other important 

 characters are: radius long and curved; ulna rudimentary; knee bend- 

 ing backward (owing to connection with the wing membrane); fibula 

 rudimentary; mammas thoracic; placenta discoidal and deciduate; 

 testes abdominal or inguinal; cerebral hemispheres smooth and not 

 extending backward over the cerebellum; presternum with noticeable 

 ''keel"; dental series including incisors, canines, premolars and molars; 

 the number of teeth variable, but never more than 38; milk teeth 

 unlike those of the permanent series. All Bats belonging to the sub- 

 order Microchiroptera have the crowns of the molars sharply tuber- 

 culate. 



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