1905. | MR. R. I. POUOCK ON A HAINAN GIBBON. 171 
decided by observing what happens in the ensuing winter, should 
the animal still be in the Gardens. Menstruation reappeared on 
Feb. 6 to 8, and has continued at tolerably regular monthly 
intervals since. Hence it may, I think, be laid down as an 
established fact that in Gibbons the interval between the men- 
strual discharges is a little over the calendar month and that the 
discharge continues for from two to three days. 
Determination of the Sex. 
When Mr. de St. Croix brought the specimen to the Gardens 
he informed me that she was a castrated male; and in support of 
his opinion drew my attention to the large size of the clitoris, 
which he most naturally mistook for the penis. The naked and 
turgid labia of the vulva he regarded as the unhealed wound 
caused by castration; and the menstrual discharge which first 
appeared in December of 19053, when the Ape was on her way to 
England, he attributed to normal bleeding induced by enforced 
sitting on the hard floor of her travelling-box. He also told me 
that it is commonly believed in Hainan that female specimens 
of the Gibbon are never brought to the coast and are practically 
unobtainable. 
There can be no doubt that this belief, coupled with the peniform 
clitoris of the Gibbon, misled Mr. de St. Croix as to the true 
sex of his animal, the castration of which, he admitted, he had 
not himself witnessed. And it seems probable that the belief 
itself is traceable to repeated mistakes on the part of Europeans 
in determining females as castrated males on account of the unusual 
length of the clitoris in these Apes as compared with the same 
organ in the Monkeys of the Old World generally. In this con- 
nection it is interesting to recall the fact that Dr. Harlan *, after 
dissection of the generative organs, described his specimen of Hylo- 
bates concolor as ‘an hermaphrodite Orang Outan.” It appears to 
me, however, that Lesson’s criticism of this opinion was perfectly 
justifiable and his decision that the specimen was an immature 
female undoubtedly correct. Pousargues, also, who evidently did 
not know Lesson’s paper, came independently to the same con- 
clusion, and stated that in the type of Hylobates nasutus, a young 
female, the clitoris was well developed and grooved below; and that 
the animal resembled in every particular, so far as the generative 
organs were concerned, the Gibbon determined as an hermaphrodite 
by Harlan. And since Harlan and two other doctors, presumably 
acquainted with human anatomy, who assisted at the dissection, 
were deceived as to the true sex of the specimen, in spite of the 
best possible opportunities for investigation, it is no wonder that 
the Europeans living in Hainan fall into a similar mistake. 
So far as can be seen, the clitoris of our Hainan Gibbon is 
like that of the specimen figured and described by Harlan, which 
resembled the penis of a Primate in a state of hypospadias. A 
* For Bibliography, see ixfra pp. 174-175. 
