90 DR, E. A. GOELDI ON MARMOSET [Jail. 15, 



Museum specimen, perhaps unduly exposed to light on the 

 shelves, because in that case such change would certainly be even 

 more noticeable in the colouring of the back, which, although 

 more exposed, still holds however its colour fast ; consequently 

 the impression is produced of a decidedly distinguishing character 

 of specific rank.) The light abdominal colour extends to the 

 under side of the insertion of the tail, as in M. rufiventer type 

 and in the other new species, M. griseovertex. 



On sepax^ating the fur the deeper portion is of the dark 

 colouring, which is lighter in the anterior than in the posterior 

 half of the body, and thus corresponding perfectly with the scale 

 of coloui'ing of the external aspect of the fur. 



The only existing specimen (stuffed) dates, as noted above in 

 the copy of the label, from Tunantins, Upper Amazon, where it 

 had been collected in 1857 by Henry W. Bates. 



Let us now proceed to the description of the type-specimen 

 of the true Midas rufiventer Gray, in the British Museum, in 

 order to relieve once for all the deplorably embarrassing situation 

 caused by the veiy defective <lescriptions given up to the present 

 time. 



Midas rufivextek. 



["Brit. Mus. Reg. 43.10.12.6. Type (skin). Locality: 

 South America. Purchased of Argent. S (skull)."] 



I must state at the outset, that I was informed by Mi-. Oldfield 

 Thomas that the specimen had been obtained from a dealer, a 

 fact which accounts for the vagueness of the locality. 



In general the results of my examination coincide with the 

 description given by Gray in his ' Catalogue of Monkeys, etc' 

 1870, p. 66, of this original specimen, only that it is too brief. 



Dorsal aspect. — Predominating colour of the back a dark 

 blackish-brown. Haiis light greyish for the apical -^ of their 

 length. Anterior pait of back less greyish, posterior part of 

 back more so. The fur down to the roots dark bi'own (not 

 light greyish-brown). 



Head (text-fig. 21). General colouring of the head a deep 

 black, not blackish-brown. Mouth bordered witli sparse whitish 

 hairs. Central zone between and beneath the nostrils sparsely 

 covered with lightish grey haii-s (not brilliantly white). 



A spear-shaped dark rust-red median stripe extending from the 

 vertex between the ears downward to the insertion of the nose, 

 the rust-red being of the same intensity as the colour of the whole 

 abdominal side. From the vertex backward, in form of a double 

 ploughshare, over the occiput down to the neck spreads out 

 a patch of a greyish-hrovjn colour, which combined with the lance- 

 shaped frontal marking forms a comparatively broad triangle with 

 a tendency to lateral posterior development. 



Arms. Outer side deep dark brown (like the head), slightly 

 lighter on the upper arm. 



