110 THE GENESIS OF SPECIES. [CHAP. 



development of species with a many facetted spheroid 

 tumbling over from one facet, or stable equilibrium, to 

 another. The existence of internal conditions in animals 

 corresponding with such facets is denied by pure Dar- 

 winians, 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 

 arid closely similar structures respectively, together with 

 palseontological considerations to be noticed later, appear to 

 point strongly in the direction of sudden and considerable 

 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 

 which 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," &c. 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." 1 



The Kev. E. 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, " under- 

 went a complete metamorphosis, having parted with its 



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



