EVOLUTION. 17 



round body and eyes on each side of its head, then 

 falls to the bottom, becomes flat, and one eye moves 

 to its top side. The crab has at first a tail appendage 

 like a lobster or shrimp. Although the frog usually 

 develops from a fish form after birth, the Surinam 

 toad brings forth perfect frogs, which, however, have 

 passed through the fish stage when within the parent's 

 body. 



It follows from these illustrations, selected from a 

 vast and constantly increasing store of facts, that no 

 animal is suddenly produced in the form of its parent. 

 They pass in the ^gg or germ state through the 

 successive stages of lower orders until they reach the 

 perfect form, or, if they are born when the process 

 has been only partially completed, they pursue the 

 upward changes after birth by the process we call 

 metamorphosis, or transformation. Therefore the 

 development of all life is similarly from lower to 

 higher forms, the difference being that sometimes 

 the changes are wholly completed within the parent's 

 body, and sometimes only partly there, the changes 

 being finished after birth. Metamorphosis, there- 

 fore, is common to all, to the dog as well as the 

 butterfly, the changes merely taking place under 

 dififerent circumstances. 



Morphology, 



Evolution is strongly supported by observation of 

 the development of separate organs of the body, the 



