560 MR. R. I. POCOCK ON THE BREEDING [May 15, 



fruits like ripe tomatoes or cherries — which are conspicuous, be it 

 noted, for the purpose of attracting attention, — no colour is more 

 conspicuous in green foliage by daylight than bright red. Red is 

 also in an eminent degree visible at a great distance in the open, 

 as a scarlet uniform proves. The crimson swelling, therefore, 

 must, it appears, reveal to the males the sex and condition of 

 adult non-pregnant females alike in the case of Mangabeys which 

 live in the forests and of Baboons which frequent open rocky 

 country. 



Again, preferential mating cannot perhaps be altogether elimi- 

 nated as a factor in the question. It may be that the colour and 

 inflammation appeal to the aesthetic sense and sexual emotions of 

 the males and act as an aphrodisiac impelling them to pair with 

 females in which the characters are pronounced rather than with 

 those in which they are poorly developed or absent. Preferential 

 mating on the part of females was regarded by Darwin and others 

 as the principal agent in fostering and fixing (not causing ah 

 initio) ornamental colour's and crests characteristic of males. If 

 females are thus influenced, why not males ? Whether or not 

 the theory can be logically and confidently applied to animals 

 probably remote from Man in mental processes, it seems illogical 

 to exclude it as a probable factor in determining the development 

 of female sexual ornamentation in the case of animals with so 

 many human attributes as Baboons and Monkeys, 



Menstrual Hcmnorrliage. 



In females of two species of Baboons, namely, a Chacma 

 {Papio porcarms) and a Yellow {P. eynocephalus)^ I have noticed 

 that the period of "heat" is hei'alded by inflammation of the 

 genito-anal area and is followed after a day or two by a show of 

 blood which continues for four or five days, dimng which time 

 the inflammatory swelling gradually increases in size. The 

 quantity of blood emitted varies greatly in the two specimens. In 

 the Chacma it is relatively small, sufficient only to stain with 

 small patches the floor of the cage ; in the Yellow Baboon, a 

 younger animal, the amount is at least ten times as great, so that 

 the cage becomes quite unsightly. It is probable, I think, that 

 the variation in the quantity given out by the two animals is 

 merely an individual characteristic and is not connected with their 

 specific distinctness. After the hfemorrhage stops, the swelling 

 continues to grow and extends laterally so as to conceal com- 

 pletely the ischial callosities and the naked skin adjacent*. It 

 reaches its maximum in about two weeks' time and remains at 

 that stage for about one week. It then begins to shrink and in 



* The swelling involves the whole of the circumanal area, so that the anal and 

 the vaginal orifices are thrust considerahlj' behind their normal jjosition. Pairing 

 between the sexes takes place after the hfemorrhage has ceased. The correlation 

 between the swelling in the female and the extreme length of the intromittent organ 

 in the male of Baboons is obvious. 



