PRIMATES FROM MADAGASCAR. 73 



There is frequent evidence of retrogressive change in brain-structure. 



Note. — The reasons which appear to justify the creation of this new family will be 

 made apparent in the detailed descriptions which follow, and more especially in 

 the final Comparative Survey. 



Subfamily Indrisin^. 



Subfossil and recent Malagasy IndrisidiB, the pithecoid affinities of which are in 

 most of the genera disguised by adaptive specialisation. 



Brain-case generally depressed; subfossil forms showing marked constriction of 

 postorbital frontal region. Nasal fossa large, with tendency in recent genera to 

 elongation of muzzle and depression of facial angle, the latter characters being less 

 marked in Mesopropitheciis. Position of lacrymal fossa variable. 



Dental formula of all genera : V^; ^q! p|^;^: "^3 - All show reduction of upper 

 third molar. Long inclined mandibular symphysis. Mandible of subfossil forms 

 massive. Auditory bullije generally present and prominent. 



Genus Pal^opropithecus (G. Grandidier). 



Definition. — Subfossil Indrisinge much specialised and probably adapted to an 

 aquatic life. Brain-case depressed with postorbital constriction. Occiput vertical, 

 lambdoidal crest frequently present. Orbits high and upwardly inclined with raised 

 margins. Postorbital bar triangular with sharp inner edge. Premaxillae send up 

 strongly developed projections which are fused to the anterior margin of nasals. 

 Zygomata high and arched. Auditory bullae absent. Series of molars and premolars 

 parallel. Mandible very massive with inclined symphysis. Lower incisors sub-equal, 

 but little inclined, and not pectinate in disposition. 



Dental formula : '■ 2: e. l: pm.2: m. 3 

 1. 2: c. 0: pm. Z : m. 3 



Pal^opropithecus maximus (Standing). (Plates X.-XV.) 



Until the discovery of the Lemuroid remains at Ampasambazimba nothing was 

 known of the skull oi Palmoprointheeus. In this locality 13 almost perfect crania 

 have been exhumed, besides numerous fragments. These, while showing considerable 

 variations in size and proportions, must all be referred to one species, to which the 

 name of Palceo])ropitlie€us maximus has been given. So far as it is possible to make a 

 comparison with the species named by Dr. Grandidier, the animal found at 

 Ampasambazimba appears to have been larger and much more massive. This will be 

 evident on a comparison of the various numbers denoting the breadth of the jaw and 

 length of the symphysis in the following table : — 



