1864.] AND DENTITION OF THE LEMURIDZ. 623 
The first lower premolar is very produced and canine-like, much 
exceeding in vertical extent the second and third premolars, which, 
judging from M. de Blainville’s figure (the second lower premolar, 
in the British Museum skull, not yet being in place), are about equal 
in this respect, and have but one large external cusp each. The 
three lower molars are subequal in size, and greatly exceed the third 
premolar, there being again a great difference in dimension between 
the latter and the first molar. The last lower molar has only a trace 
of a fifth tubercle, instead of being plainly quinquecuspid as in M. 
myoxinus, M. minor, and M. pusillus. 
On the whole I think it better, for the present at least, to associate 
the L. furcifer of De Blainville with the species just mentioned, with 
which it has so many points in common that I feel persuaded its 
tarsal structure will, on investigation, prove essentially similar. In 
the development of the first upper premolar it resembles M. typicus, 
from which, however, it appears to differ in its much longer ears and 
somewhat longer tarsus. I call it then provisionally Microcebus 
Surecifer. 
The next form, the Lepilemur mustelinus of M. Isid. G.St.-Hilaire*, 
is quite unknown to me, except from his notice and the short descrip- 
tion and the figures of the external form and dentition given by M. 
Gervaist. Dr. Gray places it in the same genus with M. furcifer, 
quoting Dr. Dahlbom to the effect that, but for the upper cutting- 
teeth, the latter would be a Lepilemur. If, however, M. Gervais’s 
representation and account of the dentition are correct, there are 
other differences besides the total absence, in the adult condition at 
least, of upper incisors ; for, in the first place, it differs from M. fur- 
cifer in that the anterior upper premolar is not caniniform, and “ ses 
molaires ont de l’analogie avec celles du Maki gris (Hapalemur) et 
des Indris ’’—certainly different enough not only from M. furcifer, 
but from any Microcebus! In the lower jaw there is an exceedingly 
large fifth tubercle to the last molar (differing in this from M. fur- 
cifer, though not from the other Mierocedi) ; and the anterior portion 
of every lower grinder is produced forwards, overlapping the postero- 
external part of the tooth next in front in quite a remarkable manner. 
The palate also (judging from M. Gervais’s figure) differs from that 
of Microcebus, in having the most anterior point of its hinder margin 
on a line with the anterior part of the last upper molar, and in having 
the posterior palatine foramina inconspicuous. Finally, the short- 
ness of the tail in this species, when considered in connexion with 
the other differences, is a very marked and exceptional character ; so 
that, I think, Lepilemur mustelinus must be considered to constitute 
a distinct genus, at all events until details as to its dentition and the 
structure of its tarsus are made known. 
The genera which have been reviewed hitherto are all from Mada- 
gascar only. The next group is composed of African species; and 
the geographical distinction is accompanied by marked structural 
differences, to which the genus Lemur (also exclusively from Mada- 
gascar) offers no exception. It would therefore have been exceed- 
* Catalogue des Primates, p. 75. t Hist. Nat. des Mammifeéres, p. 170. 
