2 ' MAMMAtilA. 



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

 importance, but only those most easily recognized: — 



Subclass EUTHERIA. 



A. Posterior limbs present. 



a. Animal not modified for flight, 

 a'. Incisors present in one or both 

 jaws, 

 rt". Incisors in front of the upper 

 and lower jaw, either not two 

 in number or not chisel-shaped, 

 rt^. Teet terminating in distinct 

 toes with claws or nails. 

 «\ Hallux or pollex or both 



opposable to other digits . 1. PRIMATES. 

 h\ Neither hallux nor pollex 

 opposable. 

 aa. Upper lip in general not 

 projecting far beyond 

 lower ; median pair 

 smaller than other in- 

 cisors 2. CARNIVORA. 



hh. Snout very pointed ; 

 upper lip projecting 

 far beyond lower ; 

 median pair of incisors 

 generally larger than 



the others 3. INSECTIVORA. 



¥. Feet either not terminating in 

 distinct toes or furnished 

 with hoofs or hoof-shaped 



nails 6. UNGULATA. 



h". Two chisel-shaped incisors in 



front of each jaAv 5. RODENTIA. 



h'. No incisors, except in certain 

 Armadillos ; Indian forms tooth- 

 less 9. EDENTATA. 



h. Animal modified for flight ; fingers 

 enormously developed to support a 

 membranous wing 4. GHIROPTERA. 



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 ; mammse 

 inguinal 7. CETACEA. 



h. Indian form heterodout : breathing- 

 orifice at end of muzzle ; no back 

 fin ; mammae pectoral 8. 8IRENIA. 



