Morphology. 59 



typical structures modified so as to perform very 

 different functions, we never find any of these 

 particular types of structure in other large branches 

 of the tree. That is to say, we never find typical 

 structures appearing except in cases where their 

 presence may be explained by the hypothesis of 

 hereditary descent ; while in thousands of such cases 

 we find these structures undergoing every conceivable 

 variety of adaptive modification. 



Consequently, special creationists must fall back 

 upon another position and say, Well, but it may have 

 pleased the Deity to form a certain number of ideal 

 types, and never to have allowed the structures 

 occurring in one type to appear in any of the others. 

 We answer, Undoubtedly such may have been the 

 case ; but, if so, it is a most unfortunate thing for your 

 theory, because the fact implies that the Deity has 

 planned his types in such a way as to suggest the 

 counter-theory of descent. For instance, it would 

 seem most capricious on the part of the Deity to have 

 made the eyes of an innumerable number of fish on 

 exactly the same ideal type, and then to have made 

 the eye of the octopus so exactly like these other eyes 

 in superficial appearance as to deceive so accomplished 

 a naturalist as Mr. Mivart, and yet to have taken 

 scrupulous care that in no one ideal particular should 

 the one type resemble the other. However, adopting 

 for the sake of argument this great assumption, let us 

 suppose that God did lay down these arbitrary rules 

 for his own guidance in creation, and then let us see to 

 what the assumption leads. If the Deity formed a 

 certain number of ideal types, and determined that 

 on no account should he allow any part of one type 



