RECENTLY LIVIXG IX THE GARDENS. 355 



It is to my mind most unlikely that four Iltjlohates males should 

 arrive in the Gardens one after the other with abnormal external 

 genital organs, and I think that in these cases the absence of 

 scrotal bag and small size of the testicles during the early years of 

 life were normal, and this opinion is strengthened by the condition 

 of some young skins in the Natural History Museum, which I 

 examined by kind permission of Mr. Old Held Thomas. The skins 

 in that collection are of difTerent ages, sizes, and species 

 (^H. hainanus, H. hoolock, H. lar, II. leitciscus, H. agilis, H. agil'is 

 ■mariiiii imd 2)ileccta, II. miilleri, H. leitcogeni/s, H. gabriellce). Some 

 of these skins, those of old males, have a laige and conspicuous 

 scrotal bag ; in others, younger males, the scrotal bag is only 

 beginning to form and not so obvious, while in some of the 

 youngest skins, one of which is the male H. liahmnv.s above men- 

 tioned, it cannot be seen or felt. In these the skin between penis 

 and ischial callosities is perfect and has not been cut at all, so it 

 is quite certain no scrotal bag existed during life. 



The delayed development of the scrotal bag and diminutive size 

 of the testicles correspond to the late commencement of menstru- 

 ation, and on this latter subject few observations have been made 

 in Hijlohates. 



I have compared the size of the skull as felt through the skin, 

 and also the canine and other teeth, of the female H. agilis now 

 living in the Gardens wath skvills in the Museum which are 

 obviously adult, and this comparison shows that the Society's female 

 //. agilis is almost adult at the present time ; although it has 

 been in pei'fect health since arrival in December 1905, it has not 

 yet begun to menstruate. Mr. Pocock has also recorded that the 

 female H. hainanus previously exhibited did not begin to 

 menstruate until almost adult (P. Z. S. 1905, vol. ii. p. 169), and 

 from these two cases it seems to be the normal course that in 

 Hijlohates menstruation is delayed until a much later period than 

 is normal in Man. 



When the female H. hainanus just mentioned was living in the 

 Gardens, I noticed that it was in proportion to height more 

 slenderly built in both body and limbs than other species (such as 

 H. agilis, H. lar, H. leuciscits, and II. hoolock) then or recently 

 living. As the animal had one fore limb, which it rarely used, 

 partially paralysed, I thought at that time the slender build was 

 the result of poor health and not a sj^ecific character. This being 

 the first female brought either alive or in skin to England, so far 

 as was known, there was nothing to compare it with, but since 

 then the male now in the Gardens arrived and showed the same 

 slender body and limbs. As this male has been in perfect health 

 since arrival in December 1907, and as its appetite is good and 

 it has not become stouter at all, although it has grown taller, 

 I think it is quite justifiable to state from these two living 

 specimens that H. hainanus is more slendei-ly built in body and 

 limbs than other species such as R. agilis, II. lar, H. hoolock, 

 and H. leuciscus. 



