6 ARKIV FÖR ZOOLOGI. BAND 8. N:0 23. 



In the northern parts of the country it was, however, never 

 observed and was replaced by Presbytis crepuscula Elliot. 



All the Langurs were as a rule very shy, and as soon 

 as they noticed any danger, they either ran away with a 

 very great speed, or concealed themselves among the luxu- 

 rious vegetation, generally at the top of the highest trees. 

 Here they could keep perfectly quiet for a long time. 



The specimen obtained is only an immature one, but 

 according to nar. G. Dollman, who kindly identified it, the 

 »general colour of the fur and character of the whiskers 

 are quite identical with those of the adult specimens in the 

 collection of the British museum». 



Skull measurements: 



Total length , ... =81,4 mm. 



Basicranial length • = 50, i » 



Condylobasal » == 59,4 » 



Occipitonasal » == 74,8 » 



Zygomatic breadtk =58,1 » 



Greatest » of brain-case = 50,6 » 



Least postorbital width = 40,6 » 



Front of canine to back of m 2 = 20,9 » 



Lengtli of upper molar series = 16, o » 



5. Hylobates lar L. — In the northern hill forests as 

 well as in the primeval forests near the Eastern coast of the 

 Gulf of Siarn (in the Chantabon province) the White-handed 

 Gibbons were very common, but both owing to their shy- 

 ness and their great rapidity when running through the 

 dense woods they are seldom observed, especially by Euro- 

 peans who are not able to penetrate the tangle of vegetation 

 as noiselessly as the natives. Only once I was lucky enough 

 to get a herd of about twenty Gibbons (males, females and 

 young) in a real good view. This occurred an early mor- 

 ning just afjter sun-rise when I was out hunting Seladang in 

 the forests near Nong Koh. I had just found a fresh track 

 of a solitary bull, when I was attracted by the shrill calls 

 which are always ending in loud wails, of the »Chanse», and 

 close by in the gigantic »Mai Yang» trees (Diplerocarpus tur- 

 binatus) a herd was leisurely feeding and playing. The great- 

 est number was black-coloured specimens, but some also be- 



