Il8 THE EVOLUTION OF MAN. 



wished to see the origin of allied species from a single 

 ancestral form proved "in special instances." Those who 

 are not satisfied with the synthetic proofs of the truth 

 of the Doctrine of Descent, as afforded by Comparative 

 Anatorr-7 and Ontogeny, Palaeontology and Dysteleology, 

 Chorology and Classification, may try to overthrow the 

 analytic proofs .in the " Monograph on Chalk . Sponges," 

 which was the product of five years of the closest observa- 

 tion. I repeat : if any one still asserts, in opposition to the 

 Theory of Descent, that the derivation of all the species 

 of a group has hitherto never been convincingly shown 

 in a special instance, the assertion is now completely with- 

 out foundation. The " Monograph on the Chalk Sponges " 

 furnishes this analytic proof in detail, entirely from facts, 

 and, as I am convinced, also with incontrovertible certainty. 

 Every naturalist who will examine the extensive material 

 used in my investigations, and follow my statements, will 

 find that in the Chalk Sponges, the various species can be 

 traced step by step through the course of their evolution in 

 statu nascenti. But, if this is really the case, if, in a single 

 class or family, the derivation of all the species from a 

 common ancestral form can be shown, then the problem of 

 the Descent of Man has been definitely solved ; and we are 

 able to demonstrate the derivation of man also from lower 

 animals. 



The demand which has been so often made, and which 

 has recently been repeated even by well-known naturalists, 

 that the derivation of Man from the lower animals, and 

 immediately from Apes, yet requires " sure proof," has thus 

 been satisfied. These "sure proofs" have been for some 

 time available to all who would open their eyes to see them 



