[ 75 ] 



VII. Osteological Contributions to the Natural History of the Chimpanzees (Troglodytes) 

 and Orangs (PithecusJ. No. IV. Description of the Cranium of an Adult Male 

 Gorilla from the River Danger, West Coast of Africa, indicative of a variety of the 

 Great Chimpanzee (Troglodytes Gorilla), with Remarks on the Capacity of the 

 Cranium and other characters shown by sections of the Skull, in the Orangs (Pithe- 

 cus), Chimpanzees (Troglodytes), and in different varieties of the Human Race. 

 By Professor Owen, F.R.S., F.Z.S., 8fc. 



Read November 11, 1851. 



The cranium of a Gorilla {Troglodytes Gorilla, Pis. XXVI. to XXVIII.) from a new 

 locality on the Western Tropical Coast of Africa — the river Danger — about 200 miles 

 distant from the Gaboon, is larger than the largest crania hitherto received by me from 

 the Gaboon, and differs remarkably in the proportions of some of its parts, not only of 

 those that relate to muscular attachments, but of parts exempt from the modifying in- 

 fluences of such. 



The bony palate (20, 21, 22), for example, is longer, narrower and deeper, as may be 

 seen by comparing PI. XXVI. with Pi. LXIII. vol. iii. ; the basioccipital ( 1 ) is longer 

 and narrower ; the vaginal process of the tympanic (v) is much more strongly developed, 

 the whole under wall of the auditory canal (v, au, and 28) being, as it were, pinched up 

 and produced downwards, the margin becoming acute as it extends mesiad and termi- 

 nating in front of the stylohyal fossa (as) ; the entoglenoid process {g) is smaller and 

 shorter, not extending one hne below the eustachian process (e) of the petrosal (16). 



When -the upper surface of the cranium of the Gorilla from the river Danger 

 (PI. XXVII.) is compared with the same part of that from the Gaboon, we see not only 

 a much greater development of the lambdoidal (s, I) and sagittal (sr, 11) intermuscular 

 crests, which are enormous in the variety figured in Pis. XXVII. and XXVIIl. (3, 11), but 

 the superorbital ridge (ir, ir, PI. XXVII.) is much more produced both upwards and 

 forwards from the plane of the forehead, as may be seen by comparing PI. XXVIIL 

 with PI. LXI. vol. iii., the side view of an equally adult male's skull of the Troglodytes 

 Gorilla from the Gaboon. In comparing the skulls of the two varieties in a direct 

 front view, the malar bones are larger, the lacrymal bones smaller, and the lacrymal 

 fossae and canals much more expanded, than in the Gaboon variety. The nasal aper- 

 ture is also wider and has more sharply defined lateral borders in that from the river 

 Danger : but the upper jaw below the nostril is not more developed, and in proportion 

 to the rest of the skull is shorter and narrower than in the variety from the Gaboon. 

 The suborbital foramina (PI. XXVII. 21) are two on one side and three on the other in 



VOL. IV. PART HI. N 



