212 



MAMMALIA. 



Trichechus (JAxm.) . TF«?rz^5. Lower jaw without 

 cutting or canine teetli ; canines of the upper jaw 

 arching downwards, in the form of projecting 

 tusks ; muzzle greatly enlarged. 



T. rosmarus. Fig. 337 ; -^ n.s. 



337 



338 



Halichoeriis (Nilsson). Four cutting- teeth to 

 each jaw ; molars simple, the lower ones with a 

 minute knob before and behind ; head flat ; muzzle 

 deep, obliquely truncate. 



H. gryf)]ius. Fig. 338 ; -^^ n. s. 



