346 SEXUAL SELECTION: MAMMALS. [Part IL 



■offers an exception, as he is provided with horns and ex- 

 serted canine teeth. But one form of weapon has often 

 been replaced in the course of ages by another form, as 

 we may infer from what follows. With ruminants the 

 development of horns generally stands in an inverse rela- 

 tion with that of even moderately well-developed canine 

 teeth. Thus camels, guanacoes, chevrotains, and musk- 

 deer, are hornless, and they have efficient canines ; these 

 teeth being " always of smaller size in the females than in 

 the males." The Camelidce have in their upper jaws, in 

 addition to their true canines, a pair of canine-shaped in- 

 cisors. 27 Male deer and antelopes, on the other hand, pos- 

 sess horns, and they rarely have canine teeth ; and these 

 when present are always of small size, so that it is 

 doubtful whether they are of any service in their battles. 

 With Ant Hope montana they exist only as rudiments in 

 the young male, disappearing as he grows old ; and they 

 are absent in the female at all ages ; but the females of 

 certain other antelopes and deer have been known occa- 

 sionally to exhibit rudiments of these teeth. 28 Stallions 

 have small canine teeth, which are either quite absent or 

 rudimentary in the mare ; but they do not appear to be 

 used in fighting, for stallions bite with their incisors, and 

 do not open their mouths widely like camels and guana- 

 coes. Whenever the adult male possesses canines now in 

 an inefficient state, while the female has either none or 

 mere rudiments, we may conclude that the early male pro- 

 genitor of the species was provided with efficient canines, 



57 Owen, ' Anatomy of Vertebrates,' vol. iii. p. 349. 



28 Sec Ruppell (in ' Proc. Zoolog. Soc.' Jan. 12, 1836, p. 3) on the 

 canines in deer and antelopes, with a note by Mr. Martin on a female 

 American deer. See also Falconer ('Palseont. Memoirs and Notes,' vol 

 l. 1868 p. 576) on canines in an adult female deer. In old males of the 

 musk-deer the canines (Pallas, 'Spic. Zoolog.' fasc. xiii. 1119, p. IS) 

 sometimes grow to the length of three inches, while in old females a ru- 

 diment projects scarcely half an inch above the gums. 



