252 MR. ST. GEORGE MIVART ON INDRIS DIADEMA. [Mar. 14, 



Fis:. 3. 



Front view of skull. Scale, nat. size. 



The skull. — De Blainville remarks * of the skull of this species, of 

 which he had only a very immature specimen, — "Tout ce que je 

 puis en dire, e'est qu'elle a la plus grande ressemblance avec une de 

 pareil age environ, provenant de VIndri ordinaire ; seulement le 

 museau est notablement plus court, I'espace inter-orbitaire un pen 

 plus large, et I'os incisif plus developpe." 



The facial part is indeed very decidedly shorter than in /. brevi- 

 caudatus, though it is longer than in I. laniger ; and the antero- 

 posterior extent of the anterior opening of the orbit falls short of 

 the length of the muzzle in front of it, though by no means so deci- 

 dedly so as in the former species. 



As in I. laniger, the skull, when viewed from above, is seen to be 

 broadest between the outer margins of the orbits ; while the greatest 

 width of the cranium proper is in a transverse line passing just be- 

 hind the posterior ends of the zygomatic arches. 



The mastoidal region, as in the other Indrisince, is not inflated, 

 but the prominence just above the aperture of the external auditory 

 meatus, which is so marked in /. laniger, is represented by only a 

 very slight enlargement in the species now described. 



The skull is not concave externally, either between the orbits or 

 elsewhere on its roof; but there is a flattening in the former situa- 

 tion, which may become a concavity with age, as this region in /. 

 hrevicaudatus thus alters with time. The same may be said with 

 regard to the development of temporal ridges, which are not indi- 

 cated in the skull examined. 



There is no interparietal. 



The nasals are rather strongly convex, and become slightly nar- 

 rower transversely towards their upper ends. They are shut out 

 from the lachrymals by a tolerably broad process of the maxilla, 

 * Loc. cif. p. 23. 



