oO Bulletin American Museum of Natural History. [Vol. XX. 



limbs, and tail deep black, with the median area of the back 

 dull black, lighter than the head, shoulders, and limbs, and 

 passing gradually into the lighter color of the flanks, many 

 of the hairs at the sides of the median area being tipped with 

 pale, glistening yellowish ; flank stripe narrow, brownish yellow 

 on the lower edge, brighter, glistening pale yellow along the 

 middle; ventral surface dull ruddy brown, with a decidedly 

 rufous tinge on the breast. The other also has the head, 

 shoulders, rump, limbs, and tail deep black, but the middle re- 

 gion of the back is brownish black, more or less suffused with 

 fulvous except along the median line; flank stripe, extending 

 from front of shoulder posteriorly to thigh, deep golden 

 rufous (in another specimen almost golden chestnut) ; ventral 

 surface rusty brown. 



52. Saimiri oerstedii (Reinh.} Six specimens, Boqueron, 

 Oct. 4-Nov. ii. Three males and two females measure as 

 follows: Total length, 687 (670-705); head and body, 295 

 (290-300); tail vertebrae, 392 (380-405); hind foot, 85 

 (76-90); ear, 25.5 (25-27). 



53. Cebus hypoleucus (Humboldt). Six specimens: 5 

 adults, Boqueron, Oct. 9~Dec. 10; i young, Boquete, Sept. 20. 



The collector's measurements of the adults are as follows: 



Total length. Head and body. Tail vertebrae. Hind foot. Ear. 



$ , 880 420 460 120 35 



$ , 783 343 440 130 3 



? , 820 390 430 123 35 



$ , 860 405 455 120 31 



? , 840 385 455 120 30 



The males and females do not appear to differ in the relative 

 elongation or color of the hair of the frontal region. 



