634 MR. ST. GEORGE MIVART ON THE CRANIA__[Nov. 22, 
in the genera Lemur*, Microcebus, and Galago, as well as in the 
Slow Lemurs. In those genera in which the number of teeth is less 
(viz. Indris, Propithecus, and Microrhynchus), the two upper and 
lower premolars appear to come into place before the last molars or 
the canines ; but I believe that, in all the genera that have thirty-six 
teeth, it is a premolar which is the last tooth to take its place in the 
permanent dentitiont, and that in all without exception the first 
molar, both above and below, is always in place before the hinder- 
most premolar. This fact establishes the dentition of Propithecus 
(and therefore doubtless of Indris and Microrhynehus also) as con- 
sisting of two premolars and three molars on each side of each jaw, 
and not (as, from the analogy of the difference between the Marmo- 
sets and the other American Monkeys, might have been considered 
not improbable) of three premolars and two molars. For M. de 
Blaimville has figured an immature Propitheeus cutting the last three 
grinders in each jaw, and the most anterior of the three is the most 
advanced. It is therefore undoubtedly a true molar, as, had it been 
a third premolar, the tooth behind it would have come into place 
long before it, instead of, as it does, after it. 
With respect to the remaining forms of Lemuride, I have it in my 
power to say but little, not having had the opportunity of seeing a 
skull either of Propithecus or of Microrhynchus. 
The dentition of Indris has been recently described by Professor 
Huxley §, who has noticed how the teeth differ in form, as well as in 
number, from those of the preceding genera. 
The skeleton of Indris is in many ways remarkable ; and it would 
be interesting to know if the other two genera with the same number 
of teeth agree with it in the largely developed paroccipital process, 
the short bony palate, and the very large mandibular angle, or in the 
remarkable antero-posterior elongation of the cervical vertebre, the 
large number of lumbar vertebree||, or in the peculiar ilium with its 
remarkable process 4 (apparently answering to the anterior inferior 
spinous process) projecting above the acetabulum. 
The skull and dentition of Microrhynchus are both figured by M. 
de Blainville**, also by Van der Hoevent++. A representation of the 
skull is also given by Vrolik tf. 
* In Hapalemur the last molar, both above and below, appears to come into 
place after the canines and premolars (see Gervais, Hist. Nat. des Mamm. p. 169) ; 
but as in this species the third premolar resembles the first molar, the apparently 
third premolars may be deciduous teeth. 
t I have seen no skulls of these species, and can only judge from M. de Blain- 
ville’s representations. 
¢ It is on this account that I think it probable that the skull of M. pusillus 
(represented by De Blainville) and the specimens (before spoken of ) of M. 
smithit are immature, the shortness of the first upper premolar being probably 
due to its not having yet fully descended. 
§ Ante, p. 326. 
|| A point of resemblance to the Slow Lemurs. 
{| Noticed by Professor Owen in the ‘ Osteological Catalogue’ of the Museum 
of the Royal College of Surgeons, vol. ii. p. 718. 
** Ostéographie, Lemur, pls. 8 & 11. 
tt Tijdschrift, pl. 1. fig. 6. 
tt Todd’s Cyclopxdia of Anatomy and Physiology, vol. iv. p. 215. 
