240 MISCELLANEOUS OBJECTIONS TO THE 



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 manner are more variable than 

 other parts of the same species. Many analogous facts, all 

 pointing in the same direction, conld 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 diiferent 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 inorganic 

 substances, or the falling of a facetted spheroid from one 

 facet to another, hardly deserve consideration. One class 

 of facts, however, namely, the sudden appearance of new 

 and distinct forms of life in our geological formations sup- 

 ports at first sight the belief in abrupt development. But 

 the value of this evidence depends entirely on the perfec- 

 tion of the geological record, in relation to periods remote 

 in the history of the world. If the record is as frag- 

 mentary as many geologists strenuously assert, there is 

 nothing strange in new forms appearing as if suddenly 

 developed. 



Unless we admit transformations as prodigious as those 

 Advocated by Mr. Mivart, such as the sudden development 

 of the wings of birds or bats, or the sudden conversion of 

 a Hipparion into a horse, hardly any light is thrown by the 

 belief in abrupt modifications on the deficiency of connect- 

 ing links in our geological formations. But against the 

 belief in such abrupt changes, embryology enters a strong 

 protest. It is notorious that the wings of birds and bats, 

 and the legs of horses or other quadrupeds, are undis- 

 tinguishable at an early embryonic period, and that they 

 become differentiated by insensibly fine steps. Embryo- 

 logical resemblances of all kinds can be accounted for, as 

 we shall hereafter see, by the progenitors of our existing 

 species having varied after early youth, and having trans- 

 mitted their newly-acquired characters to their offspring, 

 at a corresponding age. The embryo is thus left almost 



