578 THE DESCENT OF MAN. 



and thicker. If we may judge from analogy, the female 

 probably shows us in these two cases of cattle and the 

 antelope the former condition of the horns in some early 

 progenitor of each species. But why castration should lead 

 to the reappearance of an early condition of the lioriis 

 cannot be explained witli any certainty. Nevertheless, it 

 seems probable, that in nearly the same manner as the con- 

 stitutional disturbance in the offspring, caused by a cross 

 between two distinct species or races, often leads to tlie 

 reappearance of long-lost characters;* so here the disturb- 

 ance in the constitution of the individual, resulting from 

 castration, produces the same effect. 



The tusks of the elephant in the different species or races 

 differ according to sex, nearly as do the horns of ruminants. 

 In India and Malacca the males alone are provided with 

 well-developed tusks. The elephant of Ceylon is con- 

 sidered by most naturalists as a distinct race, but by some 

 as a distinct species, and here *^ not one in a hundred is 

 found with tusks, the few that possess them being exclu- 

 sively males."! The African elephant is undoubtedly dis- 

 tinct, and the female has large well-developed tusks, 

 though not so large as those of the male. 



These differences in the tusks of the several races and 

 species of elephants the great variability of the horns of 

 deer, as notably in the wild reindeer the occasional presence 

 of horns in the female Antilope Bezoarhca and their frequent 

 absence in the female of Ajitilocapra americana the pres- 

 ence of two tusks in some few male narwhals the complete 

 absence of tusks in some female walruses are all instances 

 of the extreme variability of secondary sexual characters, 

 and of their liability to differ in closely allied forms. 



Although tusks and horns appear in all cases to have 

 been primarily developed as sexual weapons, they often 

 serve other purposes. The elephant uses his tusks in 

 attacking the tiger; according to Bruce, he scores the 

 trunks of trees until they can be thrown down easily, and 

 he likewise thus extracts the farinaceous cores of palms; in 



*I have given various experiments and other evidence proving 

 that this is the case, in my " Variation of Animals and Plants under 

 Domestication," vol. ii, 1868, pp. 39-47. 



fSir J. Emerson Tennent, "Ceylon," 1859, vol. ii, p. 274. For 

 Malacca, "Journal of Indian Archipelago," vol. iv, p. 357. 



