90 On Fonr neto Amazonian Monkeys. 



without even the suffusion of rufous which occurs in both 

 species on the back. 



Skull distinguisiied by its extremely narrow interorbital 

 space and nasal opening, which is decidedly less broad than 

 high, the converse being the case in C. cupreus. 



Dimensions of the type (measured on the skin) : — 



Head and body 330 mm. ; tail 430 ; hind foot 84. 



Skull : greatest length 63 ; interorbital breadth 5 ; mas- 

 toid breadth 37; nasal opening 6*5x5; length of upper 

 premolar-molar series 15"3. 



Ilab. Teff4, Middle Amazons. 



Type. Slightly immature male. B.M. no. 8. 5. 9. 10. 

 Collected 7th June, 1906, by W. Hoffmanns. Another 

 specimen from the same place collected by Mr. H. W. Bates. 



The Museum specimens of C. cupreus, coming from the 

 Upper Pastasa R.^ the Ucayali, and the Jurua, all agree in 

 having the crown of the head distinctly more fulvous or 

 reddish than the back, and this agrees with the description 

 by Spix of his cupreus (type-locality Peruvian Amazons), 

 while the Ucayali specimens (collected by Bartlett near 

 fear;iyacu) may be taken as topotypes of Geoffroy's discolor^ 

 usually and rightly considered as a synonym of Spix^s name. 



On the other hand, the specimen obtained by Bates at 

 Ega, often mentioned in literature as being G. cupreus, 

 essentially agrees in its greyer crown and narrow nares with 

 that now again obtained in the same district by Mr. Hoffmanns. 



In Mr. Hoffmanns's collection there are two examples of 

 CaUicebus caligatus, Wagn., from Humayta, Rio Madeira, 

 some 200 miles further up the river than the type-locality, 

 Borba. These specimens indicate that G. castaneoventris, 

 Gray, may be distinguished from G. caligatus, with which it 

 is usually synonymized, by its darker colour and broader 

 interorbital space. 



Saimiri madeiroi, sp. n. 



Near S. sciurea, but the fulvous of the limbs confined to 

 the hands and feet. 



Back of the greyish fulvous characteristic of S. sciurea. 

 Crown clear grey, of a bluer tone than in sciurea, owing to 

 the almost entire absence in it of a yellowish suffusion. Fore 

 limbs from shoulders to wrists clear bluish grey, not suffused 

 with yellowish, the fulvous of the hands not extending up 

 above the wrists (except just a little way along the outer 

 border), in marked contrast to S. sciurea, in which the whole 



