74 Darwin, and after Darwin. 



details in the bodies of the higher apes. There is no 

 bone, muscle, nerve, or vessel of any importance in the 

 one which is not answered to by the other. Hence 

 there are hundreds of thousands of instances of the 

 most detailed correspondence, without there being 

 any instances to the contrary, if we pay due regard 

 to vestigial characters. The entire corporeal structure 

 of man is an exact anatomical copy of that which we 

 find in the ape. 



My object, then, here is to limit attention to those 

 features of our corporeal structure which, having 

 become useless on account of our change in attitude 

 and habits, are in process of becoming obsolete, and 

 therefore occur as mere vestigial records of a former 

 state of things. For example, throughout the verte- 

 brated series, from fish to mammals, there occurs in 

 the inner corner of the eye a semi-transparent eye-lid, 

 which is called the nictitating membrane. The object 

 of this structure is to sweep rapidly, every now and 

 then, over the external surface of the eye, apparently 

 in order to keep the surface clean. But although the 

 membrane occurs in all classes of the sub-kingdom, 

 it is more prevalent in some than in others — e.g. 

 in birds than in mammals. Even, however, where it 

 does not occur of a size and mobility to be of any use. 

 it is usually represented, in animals above fishes, by a 

 functionless rudiment, as here depicted in the case of 

 man. (Fig. lo.) 



Now the organization of man presents so many 

 vestigial structures thus referring to various stages of 

 his long ancestral history, that it would be tedious so 

 much as to enumerate them. Therefore I will yet 

 further limit the list of vestigial structures to be given 



