Chap. ix. Hybrids and Mongrels compared. 261 



variety. Hybrid plants produced from a reciprocal cross, generally 

 resemble each other closely ; and so it is with mongrel plants from 

 a reciprocal cross. Both hybrids and mongrels can be reduced to 

 either pure parent-form, by repeated crosses in successive generations 

 with either parent. 



These several remarks are apparently applicable to animals ; but 

 the subject is here much complicated, partly owing to the existence 

 of secondary sexual characters ; but more especially owing to pre- 

 potency in transmitting likeness running more strongly in one sex 

 than in the other, both when one species is crossed with another, 

 and when one variety is crossed with another variety. For instance, 

 I think those authors are right, who maintain that the ass has a 

 prepotent power over the horse, so that both the mule and the hinny 

 resemble more closely the ass than the horse ; but that the pre- 

 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 selec- 

 tion. 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 con- 

 clusion, 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 close similarity in 

 the offspring of crossed species, and of crossed varieties. If we 

 look at species as having been specially created, and at varieties as 







