8 MAMMALIA. 



ff Horns bony and solid: deciduous. 



24. CERVUS. Horns branched or palmated; while 

 growing covered with a soft velvety skin : body and limbs 

 slender : four inguinal mammae. 



** Six incisors in each jaw : two middle toes soldered 

 in one : no horns : do not ruminate. 



25. EQUUS. 



*** Six incisors in each jaw ; lower ones projecting 

 forwards: four toes on each foot; two middle 

 ones large and hoofed, lateral ones much smaller 

 and not touching the ground. 



t* 26. SUS. Tusks exserted, inclining both upwards and to one 

 side : snout elongated, and truncated at the extremity : body covered 

 with stiff bristles. 



ORDER V. CETACEA. 



Teeth various; sometimes entirely wanting: body 

 fish-shaped : anterior extremities in the form of 

 fins; posterior united, forming a flat horizontal 

 tail. 



* Grinders with fiat summits : nostrils at the ex- 

 tremity of the snout 9 not acting as blow-holes: 

 whiskers very distinct: mamma pectoral. 



(1.) MAN A TUS. Grinders eight or nine on each side above and 

 below; with two transverse ridges on the summits: no incisors or tusks 

 in the adult state : vestiges of nails on the margins of the pectoral fins. 



(2.) STELLER US. A single grinder on each side above and below ; 

 summit flat with projecting plates of enamel : fins without vestiges of 

 nails. 



