134 LECTURE IV. 



to swim with far greater facility than any other 

 quadrupeds, while, on the contrary, they walk 

 with much greater difficulty. 



In the Linngean System, in which, perhaps, 

 too great a degree of attention is paid to the cha- 

 racters of the teeth, these quadrupeds are some- 

 what awkwardly arranged; making their appear- 

 ance in detached parts of the class Mammalia. 

 In this instance therefore we shall depart from the 

 Linnaean arrangement, and pursue that of Mr. 

 Pennant and others; making a separate order 

 for the pinnated quadrupeds, which will thus be 

 made to lead, by a natural transition to the Ce- 

 taceous Mammalia, or Whales. I need hardly 

 observe, that by the pinnated or web-footed Mam- 

 malia, must be understood those only which are 

 strikingly and conspicuously distinguished by webs 

 on all their feet, and not those which are par- 

 tially web-footed, as the Otter, Beaver, and many 

 others. 



Of the truly pinnated quadrupeds we are ac- 

 quainted with but two distinct genera, viz. that 

 of Phoca or Seal, and that of Trichechus or 

 Alanati. 



The first genus, or Phoca, (Seal,) is entirely 



