MAMMALIA — QUADRUMANA, 
23 
Gray has correctly remarked, that Nyctipithecus trivirgatus, Humb., 
and N. felinus, Spix, are two very different species. The former has 
hitherto only been known from the description and drawing of Hum- 
boldt, and from a defective specimen, in which the muscles of the ear 
were almost wholly wanting, so that Gray gives it the name of Aotus^ 
and characterizes it ; pale-coloured brow^ with three narrow converging 
stripes running together on the nape, the side ones extending on to the 
cheeks ; tail remarkably dark : Brazil. I am not acquainted with this 
species, but Jhn. Natterer writes me as follows of it : — “ On the upper 
Rio Negro, I found a night ape, which presents to me too much differ-- 
ence not to separate it from the Southern Miriquina. It differs from 
this by much shorter and whiter fur — by black streaks upon the crown 
of the head, which are of equal breadth, running more apart, and almost 
parallel — by the brownish-grey- white mixed hue of the throat — the 
anterior part of the neck and the breast, — by the much paler whitish 
ochre-coloured belly — by the greyer ground-colour of the chest, without 
mixture of brownish-yellow — by a broad bright yellow-brown stripe 
from the nape to the root of the tail — by the grey tinge of the root of 
the tail, without mixture of ochre — and by hair of one colour on the 
black part of the tail. In the Miriquina of Azara, both the black side 
stripes of the crown of the head are narrower than the middle stripe, 
which is as broad again, and represents an oval spot pointed at both 
ends ; the side stripes run towards each other, and often unite with the 
middle ; throat, fore-part of neck, and all the belly, are of a pale ochre- 
colour; the general hue of the upper side is more brownish-grey, or 
yellow brownish-grey, without back stripes ; the root of the tail is ochre- 
coloured, as well as the hair of the black part of the tail at its roots ; 
the tail itself has longer hair, especially at the point. The first 
named Northern Night- Ape seems to be only a somewhat darker variety 
of the Simla trivirgata, Humb. The N. trivirgatus of Gray wiU also 
belong to it, although, in the latter, the stripes on the head unite on the 
nape, in which respect it certaiuly differs from our specimen and from 
that of Humboldt; but the difference need not be reckoned of much 
consequence, as in the Miriquina the stripes are often separated, and 
often united.” With these remarks I fully agree, and can confirm them 
in respect to the N.felinus. We distinguish, accordingly, two species, 
— 1. That of Azara, Rengger, Fr. Cuvier, Spix, and myself, described 
as Nyctipithecus Azarce^ Humb., from Paraguay and Southern Brazil, 
but stretching eastward as far as Para, where Spix found it : 2. The 
species at first described by Humboldt, now also by Gray and Natterer, 
N, trivirgatus, Humb., from the north-west of Brazil, beyond the 
Amazon, and the adjoining part of New Grenada. Lastly, a third 
species could be made, N. vociferans, Spix, dwelling in the woods of 
Tabatinga, on the coast of Peru, if the irregular colouring be present in 
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