1893.] On Megaladapis madagascariensis. 177 



marsh at Ambolisatra, on the south-west coast of Madagascar, beneath 

 a stratum of a white clayey substance (shell-marl ?) from 18 in. to 

 2 ft. in thickness. 



At first sight the skull appears to have no relation whatever with 



y known Mammalian group, either existing or extinct. 

 Its salient features are : The enormous lateral development of the 

 terior inter-orbital portion of the frontals, extending over the 

 small thick- walled orbits ; a comparatively narrow and elongate 

 post-orbital frontal region, separated by a slight contraction from the 

 equally narrow parietal region ; a thick and flattened sagittal and an 

 equally strongly-developed occipital crest. The zygomatic arch is 

 high, and projects moderately outwards. 



The brain-case is comparatively small in size, low and short, and 

 placed at a considerably higher level than the facial portion. This 

 last is elongate, with its anterior portion more elevated than the 

 posterior. The cranio-facial angle is extremely obtuse, as in most of 

 the lower Mammals, but, whilst in these the angle is open downwards, 

 in the present skull it opens upwards, owing to the fact that both 

 the facial and the cranial portions are somewhat bent upwards, the 

 former anteriorly, the latter posteriorly. 



A striking general character is the remarkable pachyostosis of all 

 the bones of the skull. 



The sutures are in great part obliterated, which, together with the 

 advanced wear of the grinding teeth, is indicative of the old age of 

 the specimen. 



The cranium, in its general physiognomy, approaches, on the one 

 hand to the South American " Howlers " (Mycetes), on the other to 

 some Marsupials, and particularly to the genus Phascolarctos. 



These resemblances the author considers to be merely isomorphisms, 

 and are not indicative of true parentage, which is to be sought 

 amongst the Lemuroiclea. Of this sub-order the present animal 

 would form a much specialised and gigantic member, being approxi- 

 mately three times the size of the largest existing Lemurids. 



In tracing cut these affinities, the author relies in the first instance 

 upon the conformation of the molars and premolars (the canines and 

 incisors are not preserved), which approach closely to the grinding 

 teeth of some Malagasy Lemurids of the genus Lepidolemur, and 

 even still more to those of Chirogaleus. 



It is further pointed out that, in its peculiar features, the skull 

 itself only carries to an extreme, characters which are present, but 

 in a much lesser degree and in varying gradations, in members of 

 the Lemuroidea, both recent (Lemuridae) and extinct (Adapidae). 



The diminutive size of the brain is viewed by the author, in this 

 instance, as a degeneracy. He anticipates that crania of young 

 specimens would present a striking approximation to existing 



VOL. LIV. N 



