278 



ANATOMY OF VERTEBRATES. 



The order Cheiroptera, with the exception of the modifica- 

 tion of their digits for supporting the wide webs that serve as 

 mngs, fig. 156, repeat the chief characters of the Insectivora ; but 

 a few of the larger species are frugivorous and have corresponding 

 modifications of the teeth and stomach. The mamm?e are pectoral 

 in position, and the penis is pendulous, in all Cheiroptera. 



The most remarkable examples of periodically torpid Mam- 

 mals are to be found in the terrestrial and volant Insectivora. 

 The frugivorous Bats differ much in dentition from the true 

 Cheiroptera, and would seem to conduct, through the Colugos 

 or Flying Lemurs, directly to the Quadrumanous order. The 



156 



Skeleton of a Bat (Pteropus). 



Cheiroptera are cosmopolitan. They have not been found in 

 older deposits than eocene tertiary. 



The order Bruta {Edentata of Cuvier) includes two genera 

 which are devoid of teeth, figs. 157 and 158 ; the rest possess those 

 organs, which, however, have no true enamel, are never displaced by 

 a second series, and are very rarely implanted in the premaxillary 

 bones. All the species have very long and strong claws. The 

 ischium as well as the ilium unites with the sacrum ; the orbit is 

 not divided from the temporal fossa. Besides the illustration of 

 affinity to the oviparous Yertebrata which the Three-toed Sloths 

 afford by the supernumerary cervical vertebras supporting false 

 ribs and by the convolution of the windpipe in the thorax, it may 



