PEIMATES FEOM MADAGaSCAE. 



151 



angle being indicated in each case by lines tangential to the forehead and median 

 incisors. 



Nasal Begion. — The length of the nasals is another supposed distinguishing feature 

 of the true Lemurs. There can be no question that the lengthening of the muzzle 

 and the concomitant development of the nasal fossa mark one of the directions in 

 which specialisation has taken place among the Malagasy Lemurs. An extreme 

 instance is offered by the newly-discovered species of Megaladapis. The most Ape- 

 like of our fossils however, especially ArcJioeolemur platyrrhinus, have comparatively 

 short and broad nasals, somewhat larger it is true than those of the Cebidse, but not 

 greatly differing from these latter either in shape or size (see text-figs. 17 & 20). 

 That the mere lengthening-out of the muzzle can in no sense be regarded as 

 differentiating the Lemurs from the Apes is at once apparent on comparing such 

 Malagasy forms as Archceolemur platyrrhinus with some of the Cercopithecidse (see 

 text-fig. 47). 



Orbital Begion. — We have already noticed one feature of the orbital region, but 

 may briefly allude to two or three others in this place. The size and obliquity of the 



Text-fig. 47. 



Truncated munzle of ArcJiceolemur platyrrhinus compared with the elongated facial portion 



of skull of Papio. 



orbits of the Lemurs have been referred to as Lemuroid features. In both these 

 respects some of our fossils range themselves rather with the Monkeys than with the 

 recent Lemurs. Again, the large extension of the lacrymal into the face, the small 

 degree to which this bone enters into the orbital wall, and the position of the lacrymal 

 fossa with its duct opening without the orbit, are further so-called Lemuroid features. 

 It is the exception, however, among the subfossii forms which we liave been studying 

 for the lacrymal foramen to open distinctly on the face, and in many cases it is as 

 much within the orbit as in certain genera of Monkeys. It is true that the lacrymal 

 bone never extends so far within the orbit in either extant or fossil Malagasy Lemurs 

 as to meet the ethmoid — there is always, so far as I have been able to observe, a 

 fronto-maxillary suture of longer or shorter extent, — but in Pakeopropithecus and 



