CETACKA. 



431 



to the same class, is strikinoly shown in the con- 



formation of the bones of the 

 anterior extremities of the Ce- 

 tacea ; for although they present, 

 externally, no resemblance to the 

 leg and foot of a quadruped, be- 

 ing fashioned into fin-like mem- 

 bers, with a flat oval surface for 

 striking the water, yet when the 

 bones are stripped of the thick 

 integument which covers them, 

 and conceals their real form, we 

 find them (as may be seen in 

 Fig. 21G) exhibiting the same 

 divisions into carpal and meta- 

 carpal bones, and phalanges of 

 fingers, as exist in the most 

 highly developed organization, 

 not merely of a Quadruped, but 



also of a Monkey, and even of Man. 



§ 3. Ainphibia. 



In the small tribe, denominated by Cuvier Aiu~ 

 p/tibia, and consisting of the P/ioca, or Seal, and 

 the Trichecus, or Walrus, we perceive that an 

 advance is made towards a fuller developement of 

 the limbs ; these animals having a distinct neck 

 and pelvis, and both hind and fore extremities. 

 In the Seal, the hind legs are drawn out posteriorly 

 to a considerable length, and placed parallel to 

 each other : when united and alternately raised and 



