On new Species 0/ Actus, 199 



XXIV. — Si.r ni>w S^peciea o/'Aotus, 

 Wy Guv DoLLMAN, B.A. 



(Published by permbsion of the Trustees of the British Museum.) 



Whilk workinn; out the collection of Douroiicoulis contained 

 in the Britisli Museum I Imvc f iiind six forms that appear 

 to belong to liitlierto uncle.scribed species, of which 1 now 

 give descriptions. 



Autus roherd, sp. n. 



Related to Aotus aznnv, llumb., but much yellower in 

 colour and with a larger skull. 



Siise and general proportions similar to A, aaarce. Hair 

 rather harsh and long, measuring about 40 mm. in length on 

 the back. General colour of upper surface of body, limbs, 

 liaiuls, and feet greyish buflf (near j)utty-colour no. 4, 'Ueper- 

 ttMre de Couleurs') ; sides of body rather greyer than back. 

 Hlaek markings on head similar in arrangement to those of 

 A. aznne, but the lateral stripes are rather indistinct and 

 tend to spread out posteriorly. Under surface of body butf- 

 coloured (yellowish butf no. li, ' llcj^ertoire de Couleurs '). 

 Undersides of limbs very similar in colour to bally, but rather 

 greyer. Uj^per surface of tail a rich tan-colour at base, 

 distal half blackish. Underside of tail similar to upper 

 surface, only the basal region is darker in colour, approaching 

 chestnut. 



Skull rather larger than that of A. aznrcp, especially the 

 orbital region ; nasals and j)alate broader. 



Dimensions of the type (measured in flesh) : — 



Head and body ;530 mm.; tail ."5 '>0 ; hind foot 90; ear 'l^o. 



Skull : greatest length G4 ; basilar length 4'5*7 ; zygomatic 

 breadth 40'5 ; greatest breadth across orbital region 43'6; 

 condylo-basilar length 48; |)alatilar length 17; length of 

 upper tooth-row, from front of first premolar to back of last 

 molar, 15. 



Uab. Serra da Chapada, Matto Grosso, Brazil. Altitude 

 2700 feet. 



Type. Adult female. B.M. no. 3. 7. 7. 14. Collected 

 28th September, 1002, by Alphonse Robert. Presented by 

 Mrs. Percy SI a den. 



Though closely allied to .-I. azarcCy the dissimilarity of the 

 skulls of the two forms, together with the differences in 

 colour, necessitate this Brazilian species being considered 

 quite distinct from the more southern form. 



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