88 Mr. O. Thomas on Four new 



EXPLANATION OF PLATE VI. 



Fig. 1. First pair of pleopoda of male of T. albidus. 



Fig. 2. Ditto ditto of T. sarsi. 



Fig. 3. Second pair of pleopoda of male of T. albidus. 



Fig. 4. Ditto ditto of T. sarsi. 



Fig. 5. Seventh perseopod of T. albidus. 



Fig. 6. Ditto of T. sarsi. 



Fig. 7. Extremity of last peduncular joint and flagellum of T. albidus. 



Note. — Figures 2, 4, and 6 have been drawn from specimens sent to me 

 by Professor Sars. 



X. — Four new Amazonian }fonkeys. 

 By Oldfield Thomas. 



Callicebus remulus, sp. n. 



Allied to C. donacophi/us, but with light crown and 

 blackish tail. 



General colour above of the grizzled greyish brown found 

 in C. donacophilus and ornatus. Crown clearer grey, the 

 frontal region almost white. Under surface and inner side 

 of limbs to wrists and ankles bright clear rufous, not the 

 muddy brownish rufous of C. donacophilus. Hands and feet 

 white — that is, the greyish white called "white" in these 

 monkeys ; about the same as in C. omattis. Front surface of 

 forearms greyish brown like body, the rufous not passing 

 round the wrist, but on the hind limbs the grey-brown 

 narrows at the ankles, the rufous of their inner surface 

 showing dorsally on ihe hallucal side ; this tendency is 

 carried further in C. ornatus, where the rufous passes right 

 round the wrists and ankles. Tail blackish throughout, the 

 hairs dull yellowish for their basal, hidden, portion, then 

 broadly black, with inconspicuous coppery or rufous tips ; at 

 the extreme end of the tail the hairs are wholly dull yellowish 

 or drab. 



Skull very much as in C. donacophilus. 



Dimensions of the type (measured in skin) : — 



Head and body 285 mm. ; tail 420 ; hind foot 82. 



Skull : greatest length 59 ; basal length 43 ; interorbital 

 space 6'3 ; premolar-molar series 14*7. 



Ilab. Santarem, Lower Amazon. 



Type. Adult female. B.M. no. 76. 6. 19. 1. Collected 

 by Mr. Wick ham. 



