CHAPTER III. 



A COMPARISON OF WHALES WITH OTHER 

 AQUATIC MAMMALS 



WHALES COMPARED TO SEALS 



IN the preceding pages a great deal has been said 

 about the influence of environment upon structure, 

 or to put the matter in a fairer way without pre- 

 judging the issue, of the connection between en- 

 vironment and structure. A study of other aquatic 

 mammals, however, and a comparison of them with 

 whales, brings out very clearly the fact that the 

 organism is not moulded in precisely the same way 

 in every case. It would be strange indeed if it were 

 so, seeing that the material upon which the same 

 influences have to work is different. 



The tribe of seals forms a very convenient starting- 

 point in such a series of comparisons, for there is 

 no doubt at all about the affinities of these marine 

 Carnivora, and they show a series of stages of more 

 and more perfect adaptation to an aquatic existence. 

 It is easy, therefore, here to distinguish between 

 structural features which are related to the aquatic 

 life and those which are definite peculiarities of the 

 group not so related. 



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