202 Mr. G. Dullmaii on 



union. Light marks above eyes buff-coloured, turning to a 

 rich brownish buff on the top o£ the liead. Under surface of 

 body pale buff (yellov/ish buff no. 1, 'Repertoire de Couleurs') ; 

 throat and chin dirty grey. Under sides of limbs greyish 

 buff. Basal portion of tail reddish (brownish terra-cotta 

 no. 1, 'Repertoire de Couleurs'), washed over with black, 

 gradually becoming blacker towards the tip, where it is 

 ahnost wholly black. 



Skull similar in size to that of A. trivirgaius ; teeth a 

 little larger, especially the last molar. 



Dimensions of the type (measured in skin) : — 

 Head and body 360 mm.; tail 310; hind foot 72. 

 Skull : greatest length 63'4; basilar length 40-5; zygomatic 

 breadth 40 ; greatest breadth across orbital region 42*5 ; 

 condyle-basilar length 45 ; palatilar length 16 ; length of 

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

 molar, 15. 



Mah. Mouth of the Rio Coca, Upper Rio Napo, Ecuador. 

 Type. Adult female. B.M. no. 0. 6. 3. 1. Collected in 

 June, 1899, and presented by Mr. W. Goodfellow. In 

 addition to the type, the Museum possesses another specimen 

 referable to this new form, also from the Upper Rio Napo. 



The well-defined V-shaped marking on the head, extending 

 back on to the neck, and the grey-coloured throat constitute 

 sufficient grounds for considering these two specimens to 

 represent a distinct species. 



Aotus lanius^ sp. n. 



A mountain form allied to Aotus trivirgatus, Humb., but 

 readily distinguished by its long thick coat and the broad 

 indistinct head-stripes. 



Hair of back very long, measuring about 60 mm. in lengtii. 

 General colour of back and upper surfaces of limbs reddish 

 brown (burnt umber no. 1, ' Repertoire de Couleurs '), 

 speckled with buff, rather greyer on flanks. Individual 

 hairs of back brownish-slate colour at base, this colour 

 extending for about half the entire length, followed by two 

 buffy-brown rings, with a black one between them, the hairs 

 terminating in a long black tip. Backs of hands and feet 

 brownish black, speckled with buff. Head-stripes brownish, 

 rather indistinct, and not extending back beyond the forehead. 

 Median stripe broad, spreading out on the forehead into a 

 fan-shaped mark. Light marks above eyes buffy. Under 

 sniface of body pinkish buff (apricot no. 1, 'Repertoire de 

 Couleurs '), gettmg paler on the flanks. Throat and chin 



I 



