244 HYBRIDS AND MONGRELS COMPARED. [CHAP. IX. 



other; whereas if two very distinct varieties of one species are 

 crossed with another species, the hybrids do not differ much. 

 But this conclusion, as far as I can make out, is founded on a 

 single experiment ; and seems directly opposed to the results of 

 several experiments made by Kolreuter. 



Such alone are the unimportant differences which Gartner is 

 able to point out between hybrid and mongrel plants. On the 

 other hand, the degrees and kinds of resemblance in mongrels and 

 in hybrids to their respective parents, more especially in hybrids 

 produced from nearly related species, follow according to Gartner 

 the same laws. When two species are crossed, one has sometimes 

 a prepotent power of impressing its likeness on the hybrid. So I 

 believe it to be with varieties of plants; and with animals one 

 variety certainly often has this prepotent power over another 

 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 genera- 

 tions 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 prepotency 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 prepotency runs more strongly in 

 the male than in the female ass, so that the mule, which is the 

 off-spring 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 inter- 

 mediate 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- 



