PEIMATES PROM MADAGASCAR. 



87 



Description of the Skull q/' Mesopropithecus pithecoides. 



The main features of the skull of Mesopropithecus may be briefly summed up. The 

 brain-case is rounded and proportionately more voluminous than that of Palceopro- 

 pithecns, and in its general conformation closely resembles that of Archceolemur. 



The frontal region is prominently convex, and the orbits comparatively small and 

 forwardly directed. The muzzle is broad and truncated. The zygomatic arches are 

 high and widely spreading, giving the skull a rounded form not seen in the present 

 Indrisinse. The profile is even more Ape-like than that of Archceolemitr (text-figs. 14 

 & 19, and PL XXL). 



Test-fig. 14. 



Profiles of (A) Mesoprojiithecus and (C) Arclueolemur compared on the one hand with (B) Indris 

 and on the other with (D) an Old World Monkej'. 



The most satisfactory method to be followed in describing the skull of Mesopro- 

 pithecus will be to compare it on the one hand with Archwoletnur, and on the other 

 with its nearest extant allies Propithecus, Indris, and Avahis. 



Such a comparison at once reveals the fact that the fossil form is robuster and more 

 massive in every way than the recent Indrisinse. Not only is it absolutely larger in 

 most of its dimensions, but the various crests and processes are much more strongly 

 developed. The comparison also shoAvs in some respects a closer resemblance to 

 Indris than to Propithecus. A quite young skull of Mesopropithecus also bears a 

 striking likeness to Avahis in general conformation (text-fig. 15). 



