ORG A NIC E VOLUTION. 65 



not till still later can it be said to which order 

 of mammals he belongs. 



Now this progressive inheritance by higher 

 types of embryological characters common' to 

 lower types is a fact which tells greatly in favour 

 of the theory of descent, whilst it seems almost 

 fatal to the theory of design. For instance, 

 to take a specific case, Mr. Lewes remarks 

 of a species of salamander — which differs from 

 most salamanders in being exclusively terrestrial 

 — that although its young ones can never 

 require gills, yet on cutting open a pregnant 

 female we find the young ones to possess gills 

 like aquatic salamanders; and when placed in 

 the water the young ones swim about like the 

 tadpoles of the water newt. Now, to suppose 

 that these utterly useless gills were specially 

 designed is to suppose design without any 

 assignable purpose ; for even the far-fetched 

 assumption that a unity of ideal is the cause 



F 



