1896. THE STUDY OF THE GIBBON. 375 



of his description of the genital organs agrees with the parts of a 

 normal female. Both the male and female organs of the gibbon are 

 somewhat peculiar, and no good description has yet been given of 

 them. Bischoff (6, 293) and Deniker (17) give descriptions of the 

 female; and Hunter (310) and Kohlbriigge (313) of both male and 

 female organs. Harlan (307) observed regular menstruation in 

 the female, but I have never observed a uterine discharge in 

 animals shot in the jungle. Deniker (17) and Kohlbrijgge (313) are 

 the only writers that describe the urinary apparatus. 



Psychology. — The gibbon is extremely difficult to get under 

 observation in the jungle, owing to its timidity and wildness. Jungle 

 notes refer only to its curious vocalisation and agile method of 

 locomotion — see Theobald (314a), Blanford (294), Anderson (291), 

 Tickell (323), Miiller (272), and Mohnike (260). Observations of its 

 habits in captivity have been made by Darwin (120), Bennet (292), 

 Hermes (139a), Klein (312), and Schmidt (^317). 



Organs of Sense. — The arrangement of the touch-papillae on the 

 hands and feet has been described by Kollmann (150), and the organs 

 of smell by Zuckerkandl (216). 



External Characters. — The young of a great number, if not all 

 species of gibbon, are born with hair of a fulvous or greyish tint, as 

 are also the young of Semnopiiheci, monkeys with v/hich gibbons have 

 structurally much in common. Between their third and fifth years, 

 however, the fulvous or grey hair of the young gibbon is replaced by 

 hair of a lighter colour — a dun, light or dark brown, or even black, 

 although many individuals retain the hair of youth throughout life ; 

 so that in nearly all species of gibbon, the hair varies in different 

 specimens from a light fulvous colour to black. A curious feature is 

 the tendency of white hair to appear in a ring round the face and on 

 the backs of the hands and feet. In H. lay, H. pileatus, and H. agilis, 

 the white circumfacial ring is complete ; in H. leucisciis and H. miielleri 

 approximately complete ; in H. hoolock it is represented only by a 

 supraorbital band ; and in H. leucogenys by an inframental stripe ; 

 while in H. syndadylus and H. [hainamis it is quite absent. Good 

 figures, showing well the external characters of H. lar, H. hoolock, and 

 H. leucogenys, are given in the Proceedings of the Zoological Society of 

 London (319, 319a). Hermes (139^) also gives a very good drawing 

 of H. lay, and Bischoff (293) a photogravure of a young specimen of 

 H. leuciscus. Bennet (292) and Horsfield (309) give descriptions of 

 H. syndadylus, and most of the authors mentioned in the section 

 dealing with classification have entered into this subject. The lines 

 on the hands and feet have been depicted by Hepburn (46) and Alix 

 (89); the tufted arrangement of the hair by Meijere (163); the 

 external ear by Keith (311a). Measurements are given by Duvernoy 

 (22), Lucae (54), Meyer (58), Hermes (139a), Tickell (323), Schmidt 

 (317), Deniker (17), Cunningham (118), and Bischoff (293). 



Distribution. — The areas occupied by the several species of 



