OBJECTIONS TO THE THEORY 343 



cies are related in the closest manner to other species 

 that still exist, or have lately existed; and it will hardly 

 be maintained that such species have been developed in 

 an abrupt or sudden manner. Nor should it be forgotten, 

 when we look to the special parts of allied species, in- 

 stead of to distinct species, that numerous and wonder- 

 fully fine gradations can be traced, connecting together 

 widely different structures. 



Many large groups of facts are intelligible only on the 

 principle that species have been evolved by very small 

 steps. For instance, the fact that the species included in 

 the larger genera are more closely related to each other, 

 and present a greater number of varieties than do the 

 species in the smaller genera. The former are also 

 grouped in little clusters, like varieties round species; 

 and they present other analogies with varieties, as was 

 shown in our second chapter. On this same principle 

 we can understand how it is that specific characters are 

 more variable than generic characters; and how the parts 

 which are developed in an extraordinary degree or man- 

 ner are more variable than other parts of the same spe- 

 cies. Many analogous facts, all pointing in the same 

 direction, could be added. 



Although very many species have almost certainly 

 been produced by steps not greater than those separating 

 fine varieties, yet it may be maintained that some have 

 been developed in a different and abrupt manner. Such 

 an admission, however, ought not to be made without 

 strong evidence being assigned. The vague and in some 

 respects false analogies, as they have been shown to be 

 by Mr. Chauncey Wright, which have been advanced in 

 favor of this view, such as the sudden crystallization of 



