MAMMALS. 13 



J Anterior and posterior limbs and pelvis well developed ; 

 femur and humerus not exserted beyond the common 

 integuments of the body. 



a. Feet with developed claws ; canines specialized ; molars, 



one or more, sectorial, adapted for cutting ; incisors 



f ; chiefly carnivorous. . . CARNIVORA, A. 



aa. Feet with hoofs ; molars mostly with grinding surfaces ; 



incisors various; no tusks; developed toes, four or 



fewer ; chiefly herbivorous. . . UNGHLATA, B. 



ff Brain with a relatively small cerebrum, leaving behind much 



of the cerebellum exposed, and, in front, much of the 



olfactory lobes. (INEDUCABILIA.) 



b. Canine teeth present, in some form ; incisors not f nor f . 

 c. Anterior limbs adapted for flight ; ulna and radius 

 united; bones of hand and fingers much elon- 

 gated, supporting a thin, leathery skin, extending 

 along sides of body to the posterior limbs; 

 mammae pectoral. . . CHIROPTERA, C. 

 cc. Limbs all adapted for walking ; ulna and radius not 

 united; hand normal; mammae usually abdomi- 

 nal IXSECTIVORA, D. 



bb. No canine teeth ; incisors f , rarely f-, chisel shaped ; 

 limbs adapted for walking. . RODENTTA, E. 



** Young born when of very small size and incomplete develop- 

 ment, never connected by a placenta to the mother ; corpus 

 callosum rudimentary. (DIDELPHIA.) . MARSUPIALIA, F. 



A. FAMILIES OF CAKNTVORA. 



* Intestinal canal provided with a coecum ; feet digitigrade ; toes 



5-4. 

 f Teeth 28 to 30 ; head broad ; snout short ; claws sharp, 



retractile FELIILE, 1. 



ff Teeth 38 to 46; snout elongated; claws bluntish, non- 

 retractile CANHXE, 2. 



** Intestinal canal without a coecum ; feet plantigrade, or, if not, 

 toes 5-5. 



