12 WALTER HE APE. 



of modification similar to that of certain females under the 

 same conditions; for instance, wapiti stags under natural 

 conditions have a special limited rutting season, but in 

 captivity (Zoo.) they rut all the year round except during the 

 season when they cast their antlers and until those structures 

 grow again. 



When rutting exists it is probably excited by similar 

 influences to those which induce the advent of oestrus in the 

 female ; on the other hand, when the sexual season of a male 

 is a permanent characteristic, either all the females of that 

 species have a sexual season all the year round or individual 

 females have different times for their sexual season. 



As examples of these two conditions it may be pointed out 

 that the camel in the Zoological Gardens of London ruts at 

 much the same time as the female camels experience oestrus 

 in Mongolia, namely, early in spring (Prejevalsky, 1876), 

 although in the Gardens there are no female camels ; while 

 the sexual passions of the dog, on the other hand, are excited 

 by oestrus of the bitch and may be called forth at any time 

 of the year. 



At the same time the proximity of the two sexes may 

 stimulate both oestrus and rutting. The stimulation of 

 oestrus is noticed in some of the larger carnivora in the 

 Zoological Gardens by the presence of the male, while I have 

 noticed rut in Semnopithecus entellus, in the Calcutta 

 Zoological Gardens, stimulated by the female; and rut in 

 the domestic rabbit stimulated by a doe under the influence 

 of oestrus. 



It is interesting to observe that while the sexual activity 

 of domestic mammals (Muller, 1838) and of wild animals in 

 captivity (Heck, 1899) may be more frequently exhibited, 

 it is not so violent as is shown by animals in the wild 



state. 



For the purposes of this paper, this is all that need be said 

 specially, regarding the generative phenomena exhibited by 

 the male ; although the activity of his generative organs may 

 be to some extent influenced by the presence or absence of the 



