140 SPECIES AND BREEDS. 



combined under a definite pattern of form which 

 characterizes its Family, — that every individual 

 exhibits structural details in the finish of its parts 

 which characterize its Genus, — and finally that 

 every individual presents certain peculiarities in 

 the proportion of its parts, in its color, in its size, 

 in its relations to its fellow-beings and the sur- 

 rounding objects, which constitute its specific 

 characters ; and all this is repeated in the same 

 kind of combination, generation after generation, 

 while the individuals themselves die. If we ac- 

 cept these propositions, which seem to me self- 

 evident, it is impossible to avoid the conclusion 

 that Species do not exist in Nature in any other 

 sense than the more comprehensive groups of the 

 zoological system. 



There is one question respecting Species that 

 gives rise to very earnest discussions in our day, 

 not only among naturalists, but among all 

 thinking people. How far are they permanent, 

 and how far mutable ? With reference to the 

 permanence of Species, there is much to be 

 ^earned from the geological phenomena belong- 

 ing to our own period, in as far as they bear 

 witness to the invariability of types during hun- 

 dreds of thousands of years at least. I hope to 

 present a part of this evidence in a future article 

 upon Coral Reefs, but in the mean time I cannot 

 leave this subject without touching upon a pom -1 



