64 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45, 



Measurements. — External measurements of type : total lengthy 

 940; head and body, 460; tail vertebrae, 480; foot, 130 (127) ; skull^ 

 greatest length, 116; basal length, 85; basilar length, 82; zygomatic 

 breadth, yy ; maxillary toothrow exclusive of incisors (alveoli), 34. 



Specimens examined. — Four, all from Siaba Bay, Nias Island. 



Remarks. — Although the characters on which this species is based 

 are slight they are very constant in the four skins as compared with 

 an extensive series of Macacus faseicularis from various localities 

 in Sumatra, the Malay Peninsula, and elsewhere. 



PRESBYTES RHIONIS sp. nov. 



Type. — Adult female (skin and skull). No. 115,665, United States 

 National Museum. Collected at Telok Pemudong, Pulo Bintang, 

 Rhio Archipelago, August 15, 1902, by Dr. W. L. Abbott. Original 

 number, 1888. 



Characters. — Like Presbytes natiincc (Thomas and Hartert), but 

 color not as dark. 



Color. — Type : general color above, from region between ears to 

 and including basal fourth of tail, broccoli-brown, washed with 

 wood-brown on shoulders and tail and with chocolate on sides and 

 lumbar region. The hairs are ecru-drab at base, and the irregular 

 appearance of this color at surface further complicates any attempt 

 at an exact description. From axilla to thigh may be traced a faintly 

 indicated dark line about 25 mm. in width bordering the whitish 

 of ventral surface. Front part of crown darker than back, the color 

 becoming almost black on forehead and temples. Feet and hands 

 blackish. On arms this color fades into the general tint of the body 

 at region of elbows, but on legs it is continued, with only a slight 

 admixture of brown, to thigh patch, and along outer side of this to 

 join the faint dark lateral stripe. Thigh patches large and con- 

 spicuous, as in Presbytes natuna:, white, slightly tinged with cream- 

 color. Above they are sharply defined from the brown lumbar 

 region, but below and at the sides they fade somewhat gradually into 

 the color of the neighboring parts. Entire ventral surface, inner 

 side of arms to elbows and of legs to knee white, tinged with gray, 

 particularly on chest and thighs. The light area on arms and legs 

 is continued to wrists and ankles, but beyond knees and elbows it is 

 much encroached upon by the dark brown. The tail darkens from 

 proximal fourth until at tip it is seal-brown. The under surface 

 is nowhere different from the upper surface. 



The series shows some trifling variations in the exact shade of the 

 dark areas, but this is chiefly due to bleaching of the hairs, and none 



