1864. ] AND DENTITION OF THE LEMURID. 633 
tunately I have been able to obtain but scanty materials from which 
to form a judgment. There are two skulls of the genus Lemur in the 
British Museum, one in the Museum of the Royal College of Sur- 
geons, and another in my own collection, all of which retain more or 
less of the milk-dentition. The skull of Microcebus furcifer in the 
national collection is also immature. 
M. de Blainville has given representations of an immature condi- 
tion of the teeth in Indris, Propithecus, Microrhynchus, and Loris*. 
M. Gervais has done the same for Hapalemur+, and Prof. Van der 
Hoeven for Perodicticust. 
Of the incisors, I may remark that the condition noticed by Sun- 
devall in a young Galago teng (namely, the presence of three inci- 
sors on each side above$) has not come under my observation. 
Of the deciduous grinders, the first upper one nearly resembles its 
vertical successor, the second has also much resemblance to the tooth 
which replaces it ; but the third upper deciduous molar (as might be 
anticipated) is very unlike its vertical successor, and very like the first 
upper molar. It has, indeed, two well-developed and pretty equal 
external cusps, one large antero-internal one, and a marked internal 
cingulum, not, however, extending so far forwards as in the first 
molar. 
In the lower jaw the first deciduous molar resembles the first pre- 
molar: but the second deciduous grinder is like the third deciduous 
one; and doth differ from their respective vertical successors, and re- 
semble the first inferior molar|]._ As I have said, the order in which 
the permanent teeth appear does not seem to be constant. For exam- 
ple, in a Lemur catta in the British Museum, the second upper pre- 
molar is coming into place while the third deciduous molar still 
remains ; in a L. macaco, on the other hand, the second upper pre- 
molar is also coming into place, but here the third deciduous molar 
is already shed, and the third premolar established in its place. In 
Microcebus furcifer the second premolar is evidently the last to 
appear both in the upper and in the lower jaw. In M. typicus the 
canines are in place, but not the third inferior premolars. In Loris 
gracilis (as represented by M. de Blainville) both the upper and lower 
canines, the large canine-like first lower premolar, and the whole of 
the molars, both above and below, appear to be in place, and yet the 
third inferior deciduous molar is retained. Altogether it is certain 
that very frequently (and, I am inclined to believe, almost, if not quite 
always) the whole of the molars, both above and below, and the 
canines come into place before some one or other of the premolars, 
* Ostéographie, Lemur, pl. 11. 
+ Hist. Nat. des Mammiferes, p. 169. 
{ Tijdschrift voor Naturlijke Geschiedenis, 1844, pl. 1. fig. 3. 
§ Kongl. Vetensk. Akad. Handling. 1842, p. 203. May not this condition 
have arisen from the coexistence of certain deciduous and permanent upper 
incisors ? 
|| In Mr. Murray’s plate of G. demédoffii (in the Edinb. New Phil. Journal, 
1859) the second deciduous inferior molar, as well as the third, is represented 
with two large, subequal, external cusps, thus agreeing with Lemur. 
4 I was unable to observe the hinder molars. 
