374 CHARLES ROBERT DARWIN. 



traordinary, if a boa-constrictor and a whale were 

 created separately, that they should be made with 

 organs which are quite useless ; while, on the 

 other hand, if they were descended from the 

 same ancestor, as other reptiles and mammalia 

 who have teeth and hind legs, they might be 

 supposed to have inherited these organs. . . . 



" Embryos of animals alike in Structure. 



"Another still more remarkable fact was that 

 pointed out by Von Baer, that the higher animals, 

 such as quadrupeds, before they are perfectly 

 formed, cannot be distinguished from the embryos 

 of other and lower animals, such as fish and rep- 

 tiles. If animals were created separately, why 

 should a dog begin like a fish, a lizard, and a 

 bird, and have at first parts which it loses as it 

 grows into its own peculiar form ? 



" Living animals of a country agree with the fos- 

 sil ones. . . . 



" We know that certain animals are only found 

 in particular countries ; kangaroos and pouched 

 animals, for example, in Australia, and sloths 

 and armadillos in South America. Now, it is re- 

 markable that all the fossil quadrupeds in Austra- 

 lia are also pouched animals, though they are of 

 different kinds and larger in size than those now 

 living; and in the same way different species of 

 sloth and armadillos are found fossil in South 

 America; while in the rocks of Europe fossil 

 mammalia are found, only slightly different from 

 those which are living there now." It seems nat- 



