172 MR. R. I. POOOCK ON A HAINAN GIBBON. [May 16, 



comparatively slight sti'uctnral modification would convert such 

 an organ into a closed tube for the passage of the urine — a fact 

 perhaps of some significance in connection with the low position 

 of the Gibbons in the Anthropomorphous series, seeing that in 

 the Lemurs, the loAvest of existing Pi'imates, the clitoris is 

 traversed by the urethral canal. 



Change of Colour. 



I am informed by Mr. de St. Croix that the young of both 

 sexes of this species are alleged by the natives to be lighter- 

 coloured at birth and for a short time afterwards than their 

 parents. His animal, when first purchased, was a dark smoky 

 grey, which, however, soon turned to black ; and perfectly black 

 she i-emained all the years she was in his possession. But within 

 a few weeks of being brought to the Gardens she began to go 

 grey, Mr. de St. Croix himself noticing a decided alteration in 

 this respect when he visited her on Mai-ch 8th, about six weeks 

 after her ai'rival in London. During the spring and early 

 summer the greyness progressed rapidly, but not quite uniformly 

 all over the body. In midsummer, according to my notes, the 

 head was black with a grey band extending on each side from 

 the eyebrow over the ear ; the beard was whitish and the nape 

 of the neck blackish ; the greater part of the body Avas blackish 

 grey, with a considerable quantity of blacker hair on the sides of 

 the belly close to the thigh and a broad triangular black patch, 

 narrower posteriorly, extending from the collar-bones on to the 

 fore part of the belly and bordered on each side by a grey area 

 paler in tone than the back ; the thigh and upper arm were 

 paler than the distal ]30i'tion of the limbs. By this time she 

 was not recognisable as the animal that reached the Gardens 

 in January. Still the greyness continued to spi'ead, the black 

 pigment died out from the areas mentioned above, lasting longest 

 upon the chest and the crown of the head. At this period she 

 presented a decided similarity to the left-hand figure on the 

 plate depicting H. jyileatus Gray (P. Z. S. 1861, p. 136, pi. xxi.), 

 although the black pectoral area was smaller and the patch on 

 the crown less sharply defined at the edges. In the early autumn 

 she was a stone or silvery grey practically all over except for a 

 black median band, fading away laterally and posteriorly, down 

 the middle line of the head. 



At the present time (May 1905) she is brownish grey or silvery 

 grey in colour, the tint varying accoi'ding to the light. The black 

 cap is still retained as a patch broadest and blackest between the 

 ears, fading into brown upon the forehead and narroAving toAvards 

 the nape of the neck. The hair on the chest has grown pale and 

 thin, showing the blackish-grey tint of the undeilying skin as 

 a dark triangular shield. On the penultimate phalanges of the 

 hands and feet the blackness of the hairs persists. The long hairs 

 on the brows are also black. 



