112 THE GENESIS OF SPECIES. [CHAP. 



with such facets is denied by pure Darwinians, but it is 

 contended in this work, though not in this chapter, that 

 something may also be said for their existence. 



The considerations brought forward in the last two 

 chapters, namely, the difficulties with regard to incipient 

 and closely-similar structures respectively, together with 

 paleontological considerations to be noticed later, appear 

 to point strongly in the direction of sudden and consider- 

 able changes. This is notably the case as regards the 

 young oysters already mentioned, which were taken from 

 the shores of England and placed in the Mediterranean, 

 and at once altered their mode of growth and formed 

 prominent diverging rays, like those of the proper Mediter- 

 ranean oyster; as also the twenty-nine kinds of American 

 trees, all differing from their nearest European allies simi- 

 larly " leaves less toothed, buds and seeds smaller, fewer 

 branchlets," etc. To these may be added other facts given 

 by Mr. Darwin. Thus he says, that " climate, to a certain 

 extent, directly modifies the form of dogs." a 



The Rev. R. Everett found that setters at Delhi, though 

 most carefully paired, yet had young with " nostrils more 

 contracted, noses more pointed, size inferior, and limbs 

 more slender." Again, cats at Mombas, on the coast of 

 Africa, have short, stiff hairs, instead of fur ; and a cat at 

 Algoa Bay, when left only eight weeks at Mombas, " un- 

 derwent a complete metamorphosis, having parted with its 

 sandj^-colored fur." * The conditions of life seem to pro- 

 duce a considerable effect on horses, and instances are 

 given by Mr. Darwin of pony breeds 4 having independent- 

 ly arisen in different parts of the world, possessing a cer- 

 tain similarity in their physical conditions. Also changes 

 due to climate may be brought about at once in a second 

 generation, though no appreciable modification is shown 



8 " Animals and Plants under Domestication," vol. i., p. 37. 

 8 Ibid., p. 47. 4 Ibid., p. 52. 



