16 THE MAMMALIA. 



in liis own way with a seemingly unim- 



:nt altt ration, which, however, changes thu 



ssi-ntially. He says : * However much 



tin- fun 11 of tlu- Rodent may vary to and fro, 



ivntly knowing no boundary, still in the end 

 found confined within the general animal 



. and must approximate either the one or the 

 other group of animals ; and thus it inclines hoth 

 to the beasts of prey as well as to Ruminants, to 



as well as to bats, and even to other inter- 

 mediate groups.' 



These similarities and parallelisms did not 

 receive much attention until Darwin's day. Darwin 



i If speaks of convergence only casually, and by 

 way of pointing out the great improbability of its 

 occurrence as the cause of agreements in organisms 

 not related by blood. But for the last ten years 

 or more, zoologists have so often been forced to 



mt for the existence of similarities and agree- 

 ments not as inherited peculiarities of race, but 



: informations and assimilations, the result of 

 outward circumstances upon the same or similar 

 original forms that this agency must be taken 

 [deration, and will be specially necessary 

 in our present inquiry, for it seems to have playrd 

 no small part in the group of the Mammalia. A 



