252 THE DESCENT OF MAN. 



Miiller found the males to be more numerous than the females. 

 According to the large experience of Mr. C. Spence Bate, the 

 reverse seems to be the case with six common British crabs, the 

 names of which he has given me. 



The proportion of the sea^s in relation to natural selection. 



There is reason to suspect that in some cases man has by selec- 

 tion indirectly influenced his own sex-producing powers. Cer- 

 tain women tend to produce during their whole lives more chil- 

 dren of one sex than of the other: and the same holds good of 

 many animals, for instance, cows and horses; thus Mr. Wright 

 of Yeldersley House informs me that one of his Arab mares, 

 though put seven times to different horses, produced seven fil- 

 lies. Though I have very little evidence on this head, analogy 

 would lead to the belief, that the tendency to produce either 

 sex would be inherited like almost every other peculiarity, for 

 Instance, that of producing twins; and concerning the above 

 tendency a good authority, Mr. J. Downing, has communicated 

 to me facts which seem to prove that this does occur in certain 

 families of short-horn cattle. Col. Marshall" has recently found 

 on careful examination that the Todas, a hill-tribe of India, con- 

 sist of 112 males and 84 females of all ages — that is in a ratio of 

 133.3 males to 100 females. The Todas, who are polyandrous in 

 their marriages, during former times invariably practiced female 

 infanticide; but this practice has now been discontinued for a 

 considerable period. Of the children born within late years, the 

 males are more numerous than the females, in the proportion of 

 124 to 100. Colonel Marshall accounts for this fact in the fol- 

 lowing ingenious manner: "Let us for the purpose of illustra- 

 "tion take three families as representing an average of the 

 "entire tribe; say that one mother gives birth to six daughters 

 "and no sons; a second mother has six sons only, whilst the 

 "third mother has three sons and three daughters. The first 

 "mother, following the tribal custom, destroys four daughters 

 "and preserves two. The second retains her six sons. The third 

 "kills two daughters and keeps one, as also her three sons. We 

 "have then from the three families, nine sons and three daugh- 

 "ters, with which to continue the breed. But whilst the males 

 "belong to families in which the tendency to produce sons is 

 "great, the females are of those of a converse inclination. Thus 

 "the bias strengthens with each generation, until, as we find, 

 "families grow to have habitually more sons than daughters." 



That this result would follow from the above form of infanti- 

 cide seems almost certain; that is if we assume that a sex- 



»' 'The Todas,' 1873, pp. 100, 111, 194, 196. 



