112 EVOLUTION AND DOGMA. 



the skin, teeth, muscles and form of the organism, 

 rendering it more fish-like in shape, and better 

 adapted for moving in the water. 



But even with all these modifications, necessi- 

 tated by changes of environment and consequent 

 mode of life, the anatomist would experience no 

 difficulty in demonstrating that the whale is not a 

 fish, but a mammal, and in exhibiting the various 

 homologies existing between the divers parts of this 

 monster of the deep, as we now know it, and parts 

 of its hypothetical terrestrial progenitor. Thus, the 

 paddles, as we have seen, correspond to the arms 

 of man, the fore-legs of quadrupeds, the flippers of 

 turtles, and the wings of birds. The hind-legs are 

 not visible, externally, it is true, but they exist in- 

 ternally in a rudimentary state. The same may be 

 said of the teeth. The fully-developed baleen whale, 

 for instance, has no teeth, for it has no need of 

 them, but in its embryotic condition it possesses a 

 complete rudimentary set of teeth, which are never 

 cut, but are absorbed during the embryonic life of 

 the organism. Similarly, the bones of the head of 

 the whale are exactly homologous with those of the 

 mammal, although the better to adapt it for aquatic 

 locomotion, the shape of the head more closely re- 

 sembles the head of a fish. But great and numer- 

 ous as are the modifications observed, they have all 

 been effected with the least possible divergence from 

 the ancestral type which is compatible with the 

 changed conditions of life. In form and in the 

 functions of certain of its parts, the whale is a fish; 

 in type and structure it is a mammal a lineal de- 



