OrperR CHIROPTERA. 
BATS. 
The order is divided into two suborders: the Megachiroptera or 
Fruit-eating Bats, containing the Old World family Pteropodide, 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 
asawing. In addition to the four elong- 
ated fingers supporting the wing mem- 
brane, there isa 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 of 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; mammez 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. 
445 
