tiew Forms 0/ Saimiri, Oryzomys, &c. 217 



tlie head deep black, the black ends to the hairs, as in S. (Ersiedi, 

 completely covering their grey bases, and rendering the whole 

 top of the head an almost unmixed glossy black. Vertical 

 dark line in front of ears strongly marked. Auricular white 

 patch well defined, sharply contrasting with the black cap ; 

 hairs on inner surface of ears yellow. Back of the same 

 grizzled yellowish as in true holiviensis. Under surface and 

 inner side of limbs proximally clear pale yellow. Forearms 

 and hands and hind feet rich golden yellow to the tips of the 

 digits ; in holiviensis the fingers and toes, beyond the meta- 

 podials, change to dull whitish yellow. Tail dull grizzled 

 yellow above, with a black tip ; clear yellow along the middle 

 line below. 



Dimensions of the typical skin : — 

 Head and body 330 millim. ; tail 400 ; hind foot 76. 

 Skull: extreme length 66; zygomatic breadth 41*5; breadth 

 of brain-case 35 ; basal length 42. 

 Hab. Cosnipata, Eastern Peru. 



Type. Male. B.M. no. 69. 5. 13. 1. Collected 19th Oc- 

 tober, 1868, by Mr. H. Whitely. 



This monkey is no doubt the " Ghrysothrix entomophaga, 

 D'Orb." of Wagner *, who looked upon his deeply black- 

 capped specimens, collected by Natterer on the Mamor^, as 

 the fully developed form of D'Orbigny's animal. But the 

 exnmples, practically topotypical, collected by Mr. Bridges 

 in Bolivia are all perfectly uniform, young and old, and it is 

 also one of these that Schlegel f, after referring to the colour 

 of the cap, states to be " tout-^-fait semblable " to a typical 

 specimen from Guarayas obtained during D'Orbigny's voyage. 

 S. h. nigriceps has just about the same deep black cap as 

 S. (Erstedi, from which it differs by its dull yellowish body. 



Oryzomys phceopus olivinus, subsp. n. 



Similar to the typical form in all essential respects, but 

 instead of the dark umber-brown of true phceopus, the general 

 colour is grizzled olivaceous or bistre, almost as in the common 

 Akodons of this region. Feet dark grey, not so blackish as in 

 phcBopus. 



Skull and teeth as in true phceopus. 



Dimensions of the type (measured in the flesh) : — 



Head and body 135 millim. ; tail (imperfect) ; hind foot 



* Wiegrn. Archiv, 1842, p. 357 ; Schr. Saujr., Suppl. v. p. 121, pi. 10 

 (1855). 



f Mon. Singes, p. 247 (1876). 



