2 INHERITANCE. Chap. XIII. 



character, and the offspring do not inherit it, the cause may 

 lie in the other parent having the power of prepotent trans- 

 mission. But when both parents are similarly characterised, 

 and the child does not, whatever the cause may be, inherit 

 the character in question, but resembles its grandparents, we 

 have one of the simplest cases of reversion. We continually 

 see another and even more simple case of atavism, though 

 not generally included under this head, namely, when the son 

 more closely resembles his maternal than his paternal grand- 

 sire in some male attribute, as in any peculiarity in the beard 

 of man, the horns of the bull, the hackles or comb of the cock\ 

 or, as in certain diseases necessarily confined to the male sex ; 

 for as the mother cannot possess or exhibit such male attri- 

 butes, the child must inherit them, through her blood, from 

 his maternal grandsire. 



The cases of reversion may be divided into two main classes 

 which, however, in some instances, blend into one another ; 

 namely, first, those occurring in a variety or race which has 

 not been crossed, but has lost by variation some character 

 that it formerly possessed, and which afterwards reappears. 

 The second class includes all cases in which an individual 

 with some distinguishable character, a race, or species, has at 

 some former period been crossed, and a character derived from 

 this cross, after having disappeared during one or several 

 generations, suddenly reappears. A third class, differing only 

 in the manner of reproduction, might be formed to include 

 all cases of reversion effected by means of buds, and therefore 

 independent of true or seminal generation. Perhaps even a 

 fourth class might be instituted, to include reversions by seg- 

 ments in the same individual flower or fruit, and in different 

 parts of the body in the same individual animal as it grows 

 old. But the two first main classes will be sufficient for our 

 purpose. 



Reversion to lost Characters by pure or uncrossed forms. — 

 Striking instances of this first class of cases were given in 

 the sixth chapter, namely, of the occasional reappearance, in 

 variously-coloured breeds of the pigeon, of blue birds with all 

 the marks characteristic of the wild Columba livia. Similar 



