172 HYLOBATES 



MULLER-S GIBBON. 



Type locality. Borneo. Type of S. concolor Harlan, not in 

 Philadelphia Academy. 



Geogr. Distr. Borneo. 



Color. Top of head, black ; back of head and upper parts of body 

 variable, gray, buflf yellow or dark broccoli brown, and in this case 

 the upper back, hind neck and shoulders are nearly seal brown; arms 

 usually the color of the upper parts, grayish, seal brown or wood 

 brown, with black on inner side ; legs gray, buff or seal brown ; side 

 of head and under parts of body black ; inner side of thighs black ; 

 of legs, similar to back. 



Measurements. Skull: occipito-nasal length, 88; Hensel, 74; 

 zygomatic width, 62 ; intertemporal width, 47 ; median length of nasals, 

 7 ; length of upper molar series, 24 ; length of mandible, 70 ; length of 

 lower molar series, 28. 



This is a most changeable species and it is quite hopeless to attempt 

 to recognize distinct forms among the variously colored individuals. 

 The animals from the south-eastern and north-western sides of Borneo, 

 have been separated as mulleri and concolor, on account of the former 

 having darker hands and feet and under parts ; but this distinction 

 does not hold good, and in the British Museum are specimens with 

 light and dark hands and feet taken in the same locality, and the under 

 parts are black or brownish black. Color in this species, as in some 

 others of the genus, has no specific value. 



The species has a gray phase, sometimes with a more or less 

 distinct blackish cap and as this certainly has some resemblance to the 

 Javan species, it was supposed that H. leuciscus inhabited both 

 islands. In respect to this Mr. Hose's testimony, given in his Mammals 

 of Borneo, 1893, p. 60, of this species is interesting. He'says, calling 

 the animal H. mulleri, "this species varies from gray to dark yellowish 

 brown, but the gray in certain lights appears pure ashy, and in others 

 of a brownish tint. In some the chest and abdomen are frequently 

 of a lighter color than the other parts, and of a brownish yellow, and 

 this seems to be the character of individuals met with on the west 

 coast of Borneo, while those inhabiting the meridional parts of the 

 island have the hands and foreparts of the body of a black brown 

 or reddish brown. In both of these varieties there is a yellowish 

 white supercilium. The last of them leads into the Hylobates from 

 the neighboring islands of Sulu to the northeast of Borneo, in which 

 the upper parts of the body are either gray or brownish, the lower 

 part of the back and loins being a little more clear than the rest. 



