VOYAGE FROM NEW YORK TO RIO DE JANEIRO. 41 



ence, and are not yet very extensively known in the com- 

 munity ; but when the facts are more fully understood, they 

 cannot fail to affect the fundamental principles of zoology. 

 I have been astonished to see how little weight Darwin 

 himself gives to this series of transformations ; he hardly 

 alludes to it, and yet it has a very direct bearing on his 

 theory, since it shows that, however great the divergence 

 from the starting-point in any process of development, it 

 ever returns to the road of its normal destiny ; the cycle 

 may be wide, but the boundaries are as impassable as if it 

 were narrower. However these processes of development 

 may approach, or even cross each other, they never end in 

 making any living being different from the one which gave 

 it birth, though in reaching that point it may pass through 

 phases resembling other animals. 



" In considering these questions we should remember how 

 slight are most of those specific differences, the origin of 

 which gives rise to so much controversy, in comparison with 

 the cycle of changes undergone by every individual in the 

 course of its development. There are numerous genera, 

 including many very closely allied species, distinguished by 

 differences which, were it not for the fact that they have 

 remained unchanged and invariable through ages, might be 

 termed insignificant. Such, for instance, are the various 

 species of corals found in the everglades of Florida, where 

 they lived and died ages ago, and had the identical 

 specific differences by which we distinguish their succes- 

 sors in the present Florida reefs. The whole science of 

 zoology in its present condition is based upon the fact that 

 these slight differences are maintained generation after gen- 

 eration. And yet every individual on such a coral stock, 

 and the same is true of any individual in any class whatso- 



