229 
somehow droppped out of the modern works. It is nowhere to be 
found in M. Isidore Geoffroy’s Catalogue of the American Monkeys 
now in the Paris Collection. What is, or was, it? 
Spix, in his large work on the Monkeys and Bats of Brazil, figured 
and described three species as new, viz. :— 
1. P. hirsuta (p. 14. t. 9), which Fischer (Syn. Mamm.) arranged 
with the subgenus Chiropotes; but it is evidently a true long-tailed 
Pithecia, and very probably P. monachus. 
2. P. inusta (p. 15. t. 109), which Fischer considers as di- 
stinct, and I believe that it is most probably the P. chrysocephala ot 
M. I. Geoffroy; but the line in the centre of the forehead has been 
overlooked, if it exists; otherwise it agrees with that animal pretty 
well. 
3. P. capillamentosa (p. 16. t. 119). Fischer considered this 
to be the same as P. rufiventer of Geoffroy and Kuhl, which appears 
very probable. But they are all so indistinctly figured and de- 
scribed, that it is very difficult to refer them with certainty to any 
of the described species. 
Some specimens of this genus having been obtained by the British 
Museum, I was induced, in the ‘ Zoology of the Voyage of H.M.S. 
Sulphur,’ published in 1842, to describe and figure the three species 
then in the Collection, and to give as correct an account of their 
synonyms as the means at my disposal then allowed. This must 
now be corrected by the additional information respecting the original 
specimens given in the Catalogue of M. Isidore Geoffroy. 
In the ‘ Catalogue Méthodique de la Collection des Mammiféres,’ in 
the Paris Museum, published in 1851 by M. Isidore Geoffroy Saint- 
Hilaire, he indicates five species of the long-tailed Pithecia, adding 
to the three species described by his father (viz. P. leucocephala, 
P. rufiventer, and P. monachus), P. chrysocephala and P. albinasa. 
The two latter he also describes at greater length in his paper on 
‘New Primates,’ in the fifth volume of the ‘ Archives du Muséum,’ 
giving a good figure of P. chrysoeephala. 
I may here observe, that two of the species which I regarded as new 
in the ‘ Zoology of the Sulphur ’—viz. P. pogonias and P. irrorata 
—appear, according to the account of M. Isidore Geoffroy, to have 
been previously described by his father, though M. Isidore Geoffroy 
does not refer to them in his synonyms. Again, that which I have 
considered to be the P. Jeucocephala of his father is evidently the 
species which M. Isidore Geoffroy has described and figured as new, 
under the name of P. chrysocephala; and here also he neglects to 
make the reference to the prior description and figure. 
We have in the British Museum thirteen specimens of this genus. 
They evidently belong to four very distinct species, of which three 
are those I described in the ‘ Zoology of the Voyage of H.M.S. Sul- 
phur,’ and the fourth the new one now first noticed, as far as I have 
been able to discover. 
The species may be divided into two sections :— 
