Chap. IX.] HYBRIDS AND MONGRELS COMPARED. 43 



potency runs more strongly in the male than in the 

 female ass, so that the mule, which is the offspring of 

 the male ass and mare, is more like an ass, than is 

 the hinny, which is the offspring of the female ass and 

 stallion. 



Much stress has been laid by some authors on the 

 supposed fact, that it is only with mongrels that the 

 offspring are not intermediate in character, but closely 

 resemble one of their parents ; but this does sometimes 

 occur with hybrids, yet I grant much less frequently 

 than with mongrels. Looking to the cases which I 

 have collected of cross-bred animals closely resembling 

 one parent, the resemblances seem chiefly confined to 

 characters almost monstrous in their nature, and which 

 have suddenly appeared — such as albinism, melanism, 

 deficiency of tail or horns, or additional fingers and 

 toes ; and do not relate to characters which have been 

 slowly acquired through selection, A tendency to 

 sudden reversions to the perfect character of either 

 parent would, also, be much more likely to occur with 

 mongrels, which are descended from varieties often 

 suddenly produced and semi-monstrous in character, 

 than with hybrids, which are descended from species 

 slowly and naturally produced. On the whole, I 

 entirely agree with Dr. Prosper Lucas, who, after 

 arranging an enormous body of facts with respect to 

 animals, comes to the conclusion that the laws of 

 resemblance of the child to its parents are the same, 

 whether the two parents differ little or much from each 

 other, namely, in the union of individuals of the same 

 variety, or of different varieties, or of distinct species. 



Independently of the question of fertility and sterility, 



in all other respects there seems to be a general and 

 22 



