CHAPTER VIII 



MARINE MAMMALS 



(Plate VIII., p. 216) 

 Section I. — Introductory Remarks 



Most of the recent writers on geographical distribution 

 have confined their attention to terrestrial Mammals, or at 

 any rate have but casually alluded to the marine groups 

 of that Class. The seven previous chapters having been 

 devoted to the terrestrial Mammals, it is proposed now to 

 examine the principal facts connected with the distribution 

 over the world's surface of the Marine or aquatic members 

 of the Class. 



Aquatic Mammals which pass their lives entirely, or 

 for the greater part, in the water are, of course, subject 

 to very different laws of distribution from the terrestrial 

 forms. As regards aquatic Mammals, land is of course 

 an impassable barrier to their extension, and, subject 

 to restrictions in certain cases, water offers them a free 

 passage. Just the opposite is the case with the terrestrial 

 Mammals, to which in most cases land offers a free 

 passage, while seas and rivers restrain the extension of 

 their ranges. 



The groups of aquatic Mammals that are represented 

 on the earth's surface at the present time are three in 

 number, viz. : (1) the Sub-order of the Carnivora, contain- 

 ing the Seals and their allies, generally called the Pinni- 



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