268 



FIRST LFSSONS IN /OOLOGY 



their pre}-. The)- arc mostl)- fur-covcrcd, and many arc 

 hunted for their skin. Tlicy have never less than four 

 toes, which are provided with strong claws that arc fre- 

 quently more or less retractile. The canine teeth are 

 usually large, curved, and pointed. 



While most of the Ycrx live on land, some are strictly 

 aquatic. The true seals, fur-seals, sea-lions, and wal- 



■*'4-- 



. 213. — A Imllal.), 7:/iOji hisoii, kilK-il lur lis skin and tonyuu, im llic 

 ]i1ains of Western Kansas tliirly }'ears ag(j. (Phi)tograi)h b\' J. Lee 

 Knitllit.) 



i-uses comprise tlie aquatic forms, all being inhabitants of 

 the ocean. The true seals, of which tlie common harbor 

 seal (Plioca vitiiliiia) \'?. our most familiar representative, 

 have the limbs so thoroughly modified for s\\ imming that 

 they arc useless on land. The fiir-scals, sea-lions, and 



