1901.] 



SKULLS or LEMURS AND MONKEYS. 



139 



it presents itself merely as a minute oblong splint of bone situated 

 in the fossa, chiefly iu front of the orbital margin, which it reaches 

 almost or entirely. In front of this rudimentary lacrymal the 

 whole of the bottom of the fossa and its raised anterior margin 

 pertain to the maxilla. Behind it, the frontal and maxilla join 

 on the orbital margin, thus forming the crista posterior and sepa- 

 rating the lacrymal from the os planum, which latter also almost 

 reaches the orbital margin from inside the orbit. There is 

 therefore no trace of di pars orhitalis lacrymalis. Neither is there 

 a lacrymo-malar suture, the latter bone being removed farther 

 backward than in any of the preceding species. 



Text-fig. 38. Text-fig. 39. 



Text-fig. 37. Orbital region of Opolenmr thomasi (Br. M. No. 91.11.30.50), 



about f nat. size. 

 Text-fig. 38. The same of Galago {Hemigalago) clemicloffi (Br. M. No. 97.12.1.5), 



about \ nat. size. 

 Text-fig. 39. The same of Galago (Hemigalago) demidoffi (Br. M. No. 98.5.4.3), 



about I nat. size. 



(Lettering as in text-fig. 26.) 



Galago {Hemigalago) demidoffi (six specimens).— Here we find a 

 moderately-sized pars orhitalis lacrymalis, and in most of the 

 specimens the crista posterior is formed by the lacrymal alone 

 (text-fig. 39). In one individual (Br. M. No. 97.12.1.4) the os 

 planum encroaches on the orbital margin, between the lacrymal 

 (laterally) and the frontal (medially), thus partaking to a slight 

 extent in the formation of the crista posterior. On the right side 

 it protrudes even on the facial part, by means of a slight process, 

 which in the fossa is situated between the maxillary (medially) 

 and the ^lacrymal (laterally). In another specimen (Br. M. 

 No. 97.12.1.5) the conditions are very similar, the os planum of 

 both sides protruding into the fossa, on the right side as far as the 

 entrance of the canalis (text-fig. 38). In the younger specimens 

 (Br. M. No. 811a and No. 98.5.4.3) the malar reaches the 

 lacrymal inside the orbit. 



