54 Bulletin American Museum of Natural History. [Vol. XX, 



fourths pale buff or buffy white, then broadly ringed with dark brown 

 and broadly tipped with pale yellowish; top of head and nape pale 

 yellowish brown; inner surface of ears, the light facial markings, sides 

 of neck, sides of shoulders, and proximal two- thirds of fore limbs white ; 

 tail very pale brownish yellow, a little darker on the terminal fifth; 

 ventral surface and flanks lighter than the back; feet dark brown; 

 dark facial markings pale chocolate brown. 



Measurements. Total length (approximate, from a flat skin, prob- 

 ably stretched), 1200; tail vertebrae, 515. (There is no skull.) 



Based on 5 flat skins (hunter's pelts), obtained by Dr. 

 Lumholtz in the vicinity of Guadalupe y Calva, southeastern 

 Chihuahua, in 1892. While very unsatisfactory material, 

 they suffice to show the existence of a pallid form of Coati in 

 this arid region. These five skins vary considerably in color, 

 individually, as Coatis usually do, but agree in the essential 

 feature of excessive pallor, as compared with specimens from 

 southern Sinaloa, Jalisco, and eastern Mexico. The general 

 character of the coloration, however, is quite different from 

 that of the pallid form from Yucatan and Brownsville, Texas. 



21. Ateles geoffroyi (Kuhl). Five specimens (2 males, 3 

 females, all adult), Pozo Azul, June 13-15 and July 5. 



The color of the upper parts varies from deep chestnut 

 rufous to pale brownish rufous, more or less suffused with 

 yellow, especially over the shoulders and anterior half of the 

 back; the lower surface is deep rich rufous in all, varying 

 somewhat in intensity in different specimens. 



The collector's measurements are as follows : 



$ , Total length, 1520; tail vertebrae, 950; hind foot, 170. 

 3,yg. ad. " " 1160; 675; 165. 



?, " 1320; " 824; " 



?, " 1250; 785; 172. 



?, 1207; 737; 178. 



The two oldest skulls measure, respectively: Basal length, 

 $ 81, $ 82; zygomatic breadth, $ 67, $ 67.5. 



22. Cebus hypoleucus (Humboldt). Five specimens, 2 

 males and 3 females, all adult, Pozo Azul, June 15 and 23 

 and July 4. 



