172 MR. R. I. POCOCK ON A HAINAN GIBBON. [May 16, 
comparatively slight structural 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 lowest of existing Primates, the clitoris is 
traversed by the urethral canal. 
Change of Color. 
IT 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 remained 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 March 8th, about six weeks 
after her arrival 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 was 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 portion of the limbs. By this time she 
was not recognisable as the animal that reached the Gardens 
in January. Still the greyness continued to spread, 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. pileatus Gray (P.Z.S8. 1861, p. 136, pl. 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 according 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 narrowing towards 
the nape of the neck, The hair on the chest has grown pale and 
thin, showing the blackish-grey tint of the underlying 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. 
