1905.] MR. R. I. POCOCK ON A HAINAN GIBBON. 171 



decided by observing what liappens in the ensuing winter, should 

 the animal still be in the Gardens. Menstruation i^eappeared 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 laig'e size of the clitoiis, 

 which he most natuiully 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 1903, when the Ape was on her way to 

 England, he attributed to normal bleeding induced by enforced 

 sitting on the hard floor of her travelhng-box. He also told me 

 that it is commonly believed in Hainan that female specimens 

 of the Gibbon are never bi-ought 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 

 leng-th 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 *, aftei- 

 dissection of the generative organs, described his specimen of Hylo- 

 hates concolor as "an hermaphrodite OrangOutan." 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 Hylohates nasutits, a young 

 female, the clitoris was well developed and grooved below ; and that 

 the animal resembled in eveiy particular, so far as the generative 

 organs were concerned, the Gibbon determined as an hermaphrodite 

 by Harlan. And since Hai-lan 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 s]3ite 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 liypospadias. A 



* For Bibliograpliy, see /w/ra pp. 174-173. 



