98 DE. H. F. STANDING ON SUBFOSSIL 



Arch^olemurs which have been found at Ampasambaziraba, since both Dr. Forsyth 

 Major and Dr. Grandidier have memoirs in hand on this subject. It will be necessary, 

 however, for the purposes of comparison, to point out the salient features of the two 

 species represented in the collection of the Malagasy Academy. I shall also in the 

 present section give a table of the chief dimensions of the complete series of 10 skulls 

 from Ampasambazimba, since the whole material will probably be no longer con- 

 veniently available for purposes of comparative study. 



It should be pointed out, in the first place, that, as in the case of Palceopropithecus, 

 there is a great variety in the size and proportions of this series of skulls. The task 

 of classifying them has been especially difficult from the fact that although various 

 characters may be pointed to as constituting marked differences in different individuals, 

 these individuals cannot be classified as showing simidtaneously the same set of 

 variations, and, moreover, intermediate types occur even in the case of the most 

 extreme divergences. As an example of this difficulty we may consider the condition 

 of the third molar. The reduced triangular shape of this tooth has been used by 

 Dr. Grandidier as forming the chief criterion for the determination of the genus 

 Bradylemur. In the series under consideration three skulls show a distinctly 

 triangular form of this tooth, two have large quadritubercular third molars, while 

 four show various conditions intermediate as to size and shape between the first and 

 second groups. Again, the attempt was made to use the facial angle as a distinguishing 

 character, and it was found that seven skulls had a long, more or less pointed muzzle, 

 so that a line tangential to the alveolar margin of the premaxillae and the frontal 

 convexity between the orbits formed approximately an angle of 60° with the plane 

 passing through the crowns of the molars and premolars. In the case of three other 

 skulls the line so drawn was more abrupt, giving an angle approaching more nearly 

 to a right angle. Again, the proportionate length of the series of molars as compared 

 with the premolars has been calculated for the whole series of skulls ; this expressed as 

 percentage-ratios gives numbers varying from 98-4 to 85-6. In one case, however, 

 the general aspect of the skull is so strikingly different in many important respects 

 from all the rest of the series that it seems justifiable to make a specific distinction in 

 this instance, and the mvae plafyrrliinus is proposed for this skull. Its distinguishing 

 features will be enumerated after a brief general description of the other members of 

 the series. I have, through the courtesy of Dr. Smith AVoodward, had the opportunity 

 of comparing these latter skulls with the type specimen of ArcJiceolemur edwardsi in 

 the British Museum and have no hesitation in referring them to this species. 



Description of Skull o/ Archseolemur edwardsi (Filhol). (Plates XVI. -XVIII.) 



The skull of Arclia'olemur edivardsi bears a close general resemblance to that of 

 Arclmolemur majori, but besides its greater size and more robust proportions, it differs 

 from this best-known species in several important particulars ; these will be referred to 

 in detail during the course of the following description. 



