SKKLETON OF SEAL 



447 



where, however, it is the 

 milk dentition that is 

 most pronounced, tlie 

 " permanent " being- 

 feeble and very early 

 shed. But the dentition 

 of the Pinnipedes pre- 

 sents other likenesses to 

 the Cetacea, which are, 

 it must be remembered, 

 regarded by some as a 

 modification of the Carni- 

 vorous stock, in which 

 case, of course, the like- 

 nesses may be genetic 

 rather than due to 

 adaptation in the two 

 cases. There is a dis- 

 tinct tendency towards a 

 homodont series, the 

 grinding teeth being 

 often very simple, and 

 the very distinct carnas- 

 sial tooth of many terres- 

 trial Carnivores being- 

 absent. Finally, the 

 number of the back teeth 

 shows some signs of being 

 on the increase ; and 

 Professor Iviikenthal has 

 found that this increase 

 is due to the division of 

 existing teeth. Here is 

 a point of likeness to the 

 many teeth of the typical 

 Toothed Whales. Dr. 

 Nehring found in several 

 examples of HaUclioerus 

 grypus the normal five 

 back teeth increased to 



