282 SEXUAL selection: mammals. Part II. 



when a tliin and narrow crest runs along the whole 

 length of the back ; for a crest of this kind would 

 afford scarcely any protection, and the ridge of the back 

 is not a likely place to be injured ; nevertheless such 

 crests are sometimes confined to the males, or are 

 much more developed in them than in the females. 

 Two antelopes, the Tragelajplius scTi]^tus^" (see fig. Q^, 

 p. 300) and Portax lyicta, may be given as instances. 

 The crests of certain staos and of the male wild sfoat 

 stand erect, when these animals are enraged or terri- 

 fied;^^ but it can hardly be supposed that they have 

 been acquired for the sake of exciting fear in their 

 enemies. One of the above-named antelopes, the Portax 

 2ncta, has a large well-defined brush of black hair on 

 the throat, and this is much larger in the male than in 

 the female. In the Ammotragiis tragela])lius of North 

 Africa, a member of the shee]3-family, the front-legs 

 are almost concealed by an extraordinary growth of 

 hair, which depends from the neck and upper halves 

 of the legs ; but Mr. Bartlett does not believe that this 

 mantle is of the least use to the male, in whom it is 

 much more developed than in the female. 



Male quadrupeds of many kinds differ from the 

 females in having more hair, or hair of a different 

 character, on certain parts of their faces. The bull 

 alone has curled hair on the forehead. -^^ In three 

 Cxosely-allied sub-genera of the goat family, the males 

 alone possess beards, sometimes of large size ; in two 

 other sub-genera both sexes have a beard, but this 



'^ Dr. Gray, ' Gleanings from the Menagerie at Knowsley,' pi. 28. 



^■* Judge Caton on the wapiti, 'Tiansact. Otiawa Acad. Nat. 

 Sciences,' 18G8, p. 36, 40; Blyth, 'Land aud Water,' on Cajra aga- 

 grus, 1867, p. 37. 



'^ 'Hunter's Essays and Observations,' edited by Owen, 1861, vol. i. 

 p. 236. 



