KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 58- NIO 2. 11 



latter in 11:0 166, but amounts to 54% in 11:0 40, and about the same, or 53,7% in the old 

 male (11:0 164). The relation between these two dimensions is thus fairly constant, which 

 means that there is about the same relative growth of the palate and the whole base 

 of the skull. 



Although the palate of these Gorillas with regard to length and narrowness - - in- 

 side m- it is even narrower than in some Baboons — much reminds about the same organ 

 of the Baboons, the Gorillas are by far not so prognathous or »dogfaced » as the Baboons. 

 This depends upon the f act that in the latter the whole molar series is situated well in front 

 of the anterior root of the zygoma, but in the Gorillas the posterior portion of the molar 

 series with m* and m s , and in young animals even m\ is pushed back below and behind the 

 root of the zygoma (Pl. III, fig. 1 & 2, Pl. IV fig. 2). By this and in consequence of 

 the size of the molars and their roots the upper jaw and the palate become placed, not 

 on alevel with the base of the skull as in the Baboons, but at a considerably lower plane. 

 A consequence of this is that ramus adscendens of the lower jaw must be much higher in 

 the Gorillas to reach its place of articulation. In fact the vertical height of the lower jaw 

 through the condyle is considerably longer than the length of the whole ramus horizon- 

 talis (Pl. III, fig. 1). 



The interorbital space increases in thickness very considerably so that it is nearly 

 three times as thick in the old male (Pl. II, fig. 1) as in the young male (n:o 166, 

 Pl. IV, fig. 3) which has only the first molar developed. This increase is not, however, 

 effected by enlargcment of the nasals, but by the processus nasales of the maxillary. 

 The nasals 011 the contrary are subjected to a relative diminution with age. In the 

 youngest of the present specimens (Pl. IV, fig. 3) the nasals have at their anterior end, 

 roughly speaking, the shape of a broad triangle which extends its base 1 along the 

 upper margin of the nasal opening and at either corner meets the ends of the premaxil- 

 laries. The combined breadth of the nasals is here about 18 mm. This triangulär 

 portions tapers very quickly in the lower part of the interorbital region to a narrow shaft 

 of a breadth hardly amounting to 2 mm. About the middle of the interorbital region 

 the nasals are again enlarged to a rhomboidal piece without mesial suture and with a 

 maximum breadth between the lateral angles of 6 mm. At the upper end this rhom- 

 boidal piece is again narrowed to a shaft, but this does not quite reach to the arcus 

 xaperciUaris. 



The conditon of the nasals of the young female 11:0 168 is similar. 



In the specimens n:os 39 (?) and 40 (d") the general shape of the nasals is similar, 

 only the size of the bones has increased, and the shaft-like process above the widened 

 rhomboidal portion has been lengthened, so that it now extends through and reaches 

 the upper frontal surface of arcus supcrciliaris. The mesial nasal suture is still partly 

 open in the triangulär lower portion and below the rhomboidal expansion. The greatest 

 combined breadth of the nasals in the triangulär portion is in n:o 40 about 26 mm., 

 that of the shaft not quite 3 mm., that of the rhomboidal expansion 7,5 mm., and above 

 the same 2,3 mm. The whole length from the mesial tip at the free margin to the posterior 

 end is about 55 mm. 



1 This base is not a straight linc, but has a projecting tip in the iniddle which, however, does not alter the 

 general shape. 



