GOIS^XOCEPHALUS. 65 



Genus GONYOCEPHALUS. 

 Kaup, Isls, 1825, p. o90. 



Tympanum distiuct. Bod}^ compressed. Dorsal scales small,, 

 uniform or intermixed with larger ones. A dorsal crest, more- 

 developed in the male than in the female. A strong transverse- 

 gular fold distinct at least on the sides. Male with a gular sac. 

 No prteanal or femoral pores. 



From Bengal and Burma to Papuasia and North-Easter n 

 Australia. 



Four species in the Malay Peninsula. 



Mr. Kobinson has repeatedly observed the curiously sluggish 

 liabits of the adult, making no efforts to escape when seized, 

 though biting viciously ; young individuals, however, are ex- 

 ceedingly active and difficult to capture. 



Si/nopsis of the Sj^)ecies. 



I. Enlarged scales scattered on the sides; nuchal 



and dorsal crests continuous, very high in 



the male ; fourth finger slightly longer than 



third. 



Dorsal, gular, and ventral scales keeled G. borneensis, p. 65. 



Dorsal and gular scales smooth, ventrals smooth 



or faintly keeled G- herveyi, p. C6. 



II. No enlarged scales on the sides. 



Nuchal and dorsal crests very high in the male, 

 separated by a notch ; gular and ventral scales 

 smooth; third and fourth lingers equal; 

 tympanum naked G- (jrandis, p. G6. 



Nuchal and dorsal crests continuous, the latter 

 low: gular scales smooth, ventrals keeled; 

 fourth finger slightlv longer than third ; tym- 

 panum partly covered with scales G. rohnsomt, p. 67. 



64. Gonyocephalus horneensis. 



Lop/n/ms borneensis, Sclileg. Bijdr. tot de Dierk. i, p. G, pi. iii, fig. 2 



n 84:8) 



Gonyocephalus horneensis, Bouleng._ Cat. Liz. i, p. 288 (1885) ; id. 



op. cit. ni 

 id. J our 



ii,p. 493 (1887) ; id. Fascic. Malay., Zool. i, p. 153 (190o) : 



■n. Fed. Mai. St. Mus. iii, p. 65 (1908). 

 Tympanum smaller than eye-openiug ; upper head-scales small, 

 keeled- 9 to 12 upper and as many lower labials; gular sac 

 moderately large ; gular scales keeled. Nuchal and dorsal crests 

 continuous, formed of long slender lobes, which are longest on the 

 nape (as long as snout in the male), and generally decrease m 

 size on the back, with smaller keeled scales at the base. Dorsal 

 scales small, obtuselv keeled, the points directed upwards and 

 backwards, with a few enlarged scattered scales on the sides ;. 



