2 MAMMALIA. 



following table : these characters are not always those of the greatest 

 importance, but only those most easily recognized: 



Subclass EUTHEEIA. 



A. Posterior limbs present. 



a. Animal not modified for flight. 



a'. Incisors present in one or both 



jaws. 



a". Incisors in front of the upper 



and lower jaw, either not two 



in number or not chisel-shaped. 



d\ Feet terminating in distinct 



toes with claws or nails. 

 a 4 . Hallux or pollex or both 



opposableto other digits . 1. PRIMATES. 

 b 4 . Neither hallux nor pollex 



opposable. 



aa. Upper lip in general not 

 projecting far beyond 

 lower ; median pair 

 smaller than other in- 

 cisors , 2. CARNIVORA. 



bb. Snout very pointed ; 



^**> upper lip projecting 



far be} 7 ond lower ; 



median pair of incisors 



generally larger than 



the others 3. INSEGTIVORA. 



3 . Feet either not terminating in 

 distinct toes or furnished 

 with hoofs or hoof-shaped 



nails 6. UNGULATA. 



b". Two chisel-shaped incisors in 



front of each jaw 5. RODENT I A. 



b'. No incisors, except in certain 

 Armadillos ; Indian forms tooth- 

 less 9. EDENTATA. 



b. Animal modified for flight ; fingers 



enormously developed to support a 



y membranous wing 4. CHIROPTERA. 



B. No external posterior limbs ; body 

 modified for swimming. 



a. Homodont or toothless : breathing- 



orifice generally on top of head ; 

 a back fin in most genera ; mammae 

 inguinal 7. CETACEA. 



b. Indian form heterodont : breathing- 



orifice at end of muzzle; no back 



fin ; mammae pectoral 8. SIRENIA. 



