366 



THE INFLUENCE OF LIVING SUKROrNDINGS. 



are frequently very variable in tteir peculiarities. This last 

 circumstance has given rise quite recently to an objection to the 

 applicability of Darwin's principles which I will here take the 

 opportunity of discussing briefly. 



Kramer asserts, on the ground of a very elaborate mathe- 



Fio. SB.— Cladogmlhus dormlis, Eriolison. In the four coriiei-s iu-e four different forms 

 of the male ; the lower form on the left has mandibles hardly larger than those of the 

 female in the middle, Natural size. 



matical calculation on the method of the doctrine of chances, 

 that, assuming Darwin's principles as the basis of such a calcu- 

 lation, the extreme forms of a series of varieties must be less 

 numerous than the intermediate forms, and in the same way that 

 the production of excessive deviations must also be possible ; 



