18(37] Mil. ST. GEORGE MIVART ON TH IC I.EMURID E. 969 



figure* as regards the large fifth tubercle to the .ast lower molar, 

 the shortness of the palate, and the inconspicuousness of the poste- 

 rior palatine foramina. But not only do thej' differ from Microcebus 

 and Cheirogaleus as regards the two points last mentioned ; they 

 differ also both from Lemur and Hapalemur in that the mastoidal 

 region of the periotic is enlarged and inflated. 



As in Microcebus and Cheirogaleus, each upper premolar has but 

 one external cuspf; but the third upper premolar is relatively larger 

 than in those genera, so that each upper dental series increases in 

 size from before backwards to the penultimate molar in a more gra- 

 dual manner. 



The skull, when viewed from above, is seen to be broadest between 

 the outer margins of the orbits, and the cranium proper to be so 

 just behind the posterior roots of the zygomata. 



The muzzle is longer than the antero-posterior extent of the ante- 

 rior margin of the wide orbit. The upper surface of the skull is 

 concave between the orbits ; there is a more or less marked sagittal 

 ridge ; and a rather deep depression exists on each^ide of the muzzle 

 innnediately in front of the lachrymal foramen J, which last is placed 

 w'eU upon the check. 



Tbe sphenoidal fissure and the foramen rotundum are together 

 represented by a single opening. There is no carotid foramen in 

 the basis cranii ; and the malar foramen is very minute. The poste- 

 rior palatine foramina are small, and there are no defects of ossifica- 

 tion on the palate ; but the anterior palatine foramina are large. The 

 posterior margin of the palate extends but little backwards, its middle 

 being in a line with the anterior end of the posterior third of the 

 upper penultimate molar. The postglenoid process is large, and 

 behind it is a postglenoidal foramen. 



The prsemaxilla is (as might be expected from the absence of 

 upper incisors) very small, and quite, or all but, invisible when the 

 skull is viewed in profile ; yet it sends up a small process which joins 

 the nasal ; and the latter bone is separated, on each side, from the 

 lachrymal by an ascending process of tlie maxilla. There is no par- 

 occipital process. The mandible has a lofty coronoid process, and 

 the angle is produced downwards as well as backwards. 



Tiie dentition may be expressed by tlie formula : — 



The upper canine is very large, with a strongly marked vertical 

 internal groove and a posterior basilar process. The three upper 

 premolars decrease (from before backwards) in vertical extent, but 

 increase in breadth. Each of the first two upper molars consists of 

 two well-marked external cusps, of a very large antero-iuternal cusp, 

 connected with the postero-external one by an oblique ridge, and of 



* Hist. Nat. de-s Mammiferes, p. 170. 

 t As noticed bv Messrs. Sclilegel aud Pollen, /. c. p. 11. 



{ A similar depression exists in (J. milii and C. furcifer, and is relatively 

 deeper and still more sharply defined in M. minor. 



Proc. Zool. Soc— 1867, No. LXII. 



