CHAPTER XIII 



THE ORDER CHIROPTERA 



Mammals, having their fore limbs specially modified for flight. 

 The forearm consists of a rudimentary ulna, and a long curved 

 radius. The carpus has six bones supporting a small pollex and 

 four greatly elongated fingers, between which and the sides of 

 the body and the hinder extremities a thin expansion of the 

 integument (the wing-membrane or patagium) is extended. The 

 knee is directed backwards, owing to the rotation of the hind limb 

 outwards by the wing-membrane ; a peculiar elongated cartilaginous 

 process (the calcar), rarely rudimentary or absent, arising from the 

 inner side of the ankle-joint, is directed inwards, and supports part 

 of the posterior margin of an accessory membrane of flight, extending 

 from the tail or posterior extremity of the body to the hinder limbs 

 (the inter-femoral membrane). The penis is pendent; the testes are 

 abdominal or inguinal ; the mammary glands thoracic and generally 

 postaxillary ; the uterus is simple or with more or less long cornua ; 

 the placenta discoidal and deciduate ; and the smooth cerebral 

 hemispheres do not extend backwards over the cerebellum. The 

 dental series includes incisors, canines, premolars, and molars and 

 never exceeds i f , c -\, p f , m •§ ; total 38. 



The animals comprised in this order are at once distinguished 

 by the presence of true wings, and this peculiarity is accompanied 

 by other modifications of bodily structure having special relation to 

 flight. Thus, in contrast to most other mammals, in which the hind 

 limbs greatly preponderate in size over the fore, in the present 

 order the fore limbs immensely exceed the short and weak hinder 

 extremities. The thorax, as giving origin to the great muscles 

 which sustain flight, and containing the proportionately large lungs 

 and heart, is remarkably capacious, and the ribs are flattened and 

 close together ; the shoulder -girdle is also greatly developed in 

 comparison with the weak pelvic bones. 



Linnaeus included the Bats among the Primates, mainly on 



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