1901.] SKDLLS OF LEMUllS AND MONKEYS. 143 



Chirogale. 



Oh. milii (5 specimens). — The lacrymal is broad and chiefly 

 facial. Anteriorly the fossa lacrymalis is bordered by the maxillary. 

 There is a fronto -maxillary suture, the lacrymal not meeting the 

 nasal. The malar joins the lacrymal on the orbital margin and 

 within the orbit. The small orbital portion of the lacrymal is 

 delimited behind in the same manner as in Ojjolemur. In one 

 youngish specimen only (Br. M. Z. D, No. 88.2.18.3) a very small 

 distinct os planum appears between tl»e maxillary and frontal, 

 articulating besides in front with the lacrymal. In aged specimens 

 the lacrymal sutures are mostly obliterated, the lacrymal uniting 

 with the maxillary. 



" Chirogale'' trichotis, Gunth. (Br. M. Z. D. No. 75.1.29.2).— 

 The facial cranium is more drawn out than in the former species, 

 and in connection with this the lacrymal fossa has a more 

 anterior position ; as usual, it is bordered in front by the 

 maxillary. 



3Iycetes. 



Fortj^-oue skulls have been examined. — Only in fifteen specimens 

 the lacrymal fossa is wholly encircled by the lacrymal bone, as 

 described and figured ^ by Gegenbaur ; the anterior boundary 

 of the fossa, which protrudes on the cheek, increases with the age 

 of the animal, the whole of the lacrymal assuming in old individuals 

 (PL XI. fig. 6) a more oblique position, in accordance with the 

 general direction of the facial cranium. In twenty-two cases the 

 maxilla partakes to a slight extent in the forming of the antero- 

 inferior margin of the fossa ; this is nearly always the case in vei'y 

 young specimens (PI. XI. fig. 3); but it may occur also in very old 

 individuals (e. g., M. senicuhis, Br. M. No. 44 e). A lacrymo-nasal 

 suture occurs almost without exception ; in very youug specimens 

 the two bones may barely touch each other, without a true suture 

 being formed. In one of the two youngest specimens available 

 (M, senicuhis, Leyden Mus. r ; d. 1 not quite protruded), a pointed 

 process of the maxillary reaches the frontal on the left side, on the 

 right a minute Wormian bone is interposed. In the second speci- 

 men, which I owe to Prof. Eud. Burckhardt (the deciduous incisors 

 and d. 3 alone in place), a comparatively elongate lacrymo-nasal 

 suture is present on both sides. 



As in the following genus, it is sometimes a matter of mere 

 individual appreciation whether to consider the lacrymal fossa as 

 intra- or extra-orbital ; in fact in some cases it is neither inside 

 nor outside the orbit. Of course, it depends where we draw the 

 limits of the orbita ; but when there are no definite limits, this 

 becomes a matter of some difficulty. 



^ Op. cit. p. 175, fig. TI A. 



