CHIROPTERA 261 



Order Chiroptera. (Bats.) • 



Fore limbs modified for flight by the elongation of the fore- 

 arm and fingers ; fore and hind limbs connected by a membraneous 

 expansion of the skin, this frequently including the tail : humerus 

 and femur extending beyond the body; bones of the forearm 

 imited : ulna reduced to a nidiment : hind limbs so far rotated that 

 the knee bends outward and backward ; a cartilagineous calcar on 

 the inner side of the ankle of the hind foot supporting a part of 

 the interfemoral membrane; teeth enveloped in enamel and con- 

 sisting of incisors, canines, premolars and molars. 



The highly specialized order of Bats is widely distributed 

 over the g-lobe excepting in the polar regions. The order con- 

 sists of two su1x)rders and six families. One suborder (Mcga- 

 chiroptera) does not occur on this continent. Its members feed 

 principally on fruit. Some species are very large, such as the so- 

 called Flying Foxes, some of which are as large a as large hawk, 

 while other species are quite small. 



The wings of Bats consist of a web-like expanjion of the 

 skin from the upper and lower surfaces of the body, these two 

 layers being thin, coherent and expanded by a framework con- 

 sisting of the greatly lengthened bones of the fingers and arms and 

 the more or less lengthened and exserted legs ; the membrane be- 

 ing continued from the end of the inner finger to the foot ot the 

 hind leg and usually to the tail. The flight of a bat is not as 

 graceful as that of a bird, but it is nearly as rapid and more com- 

 pletely under control in making rapid turns. They are as awk- 

 ward in walking on the ground or other surfaces as they are dex- 

 trous on the wing. 



The eyes of bats are small and of less service than most other 

 of their senses. The organs of smell are well developed. The 

 sense of touch or feeling is highly developed, especially in the 

 wing membranes and nasal appendages of the "leaf-nosed" 

 species. The hearing is very acute and is probably the most use- 

 ful sense in locating their insect prey. 



Bats are crepuscular and nocturnal, rarely going abroad in 



