36 SMeton of the Gorilla. 



surface of the skull in tlie gorilla and macaque slopevS 

 towards the foramen rtxagnum, or place of junction of the 

 cranial and spinal cavities, and is externally concave. In 

 man, this same region is convex. The plane of the foramen 

 rmagnum is inclined to that of the horizon in the gorilla 

 and macaque, and the head is not balanced on the top of the 

 spinal column, as in man ; and in the gorilla, owing to the 

 great development of the bones of the face, requires a 

 development of the muscles of the back of the neck to 

 uphold it, as is evidenced by these brutal spinous processes. 

 The swpTa-orhital ridges are strongly marked, both in gorilla 

 and macaque, and, as has been remarked by Professor Owen, 

 it is difficult to conceive, upon the ' derivative hypothesis,' 

 what external influence could produce them, seeing that 

 they are quite without the influence of any muscular action 

 whatever. Owen says further, that where they bend down 

 to meet the malar bones, and form the outer boundary of 

 the orbit, if viewed from the side, no part of the orbit is 

 seen in advance of this border. In these specimens, how- 

 ever, and in macaque, a small part of the lachrymal bone is 

 still seen. In man, the outer wall of the orbit is less promi- 

 nent, so that he can, by simiply turning the head, the body 

 remaining fixed, see all points of the horizon, a provision in 

 harmony with his usual erect attitude, and especially made 

 use of when flying from a pursuer, whether on horseback or 

 on foot, and in the more genial though not less stirring 

 contests of the course, &c. The Post condyloid process of 

 the squamosal, or middle root of the zygoma, is so large in 

 in both gorilla and macaque as entirely to separate the con- 

 dyle of the lower jaw from the auditory process, which is not 

 the case in man. There are many points of great interest in 

 this region too minute for notice this evening. The gorilla 

 makes some approach to the possession of a riiastoid p)rocess, 

 whereas in macaque there is none. The articulated condition 

 of these skeletons prevents my following out the comparisons 

 of the interior of the skull. I have, however, in my Lines 

 of Demarcation betiueen Man, Gorilla, and Macaque, care- 

 fully examined all that has been said on this subject by 

 Professor Owen. As his papers in the Zoological Society's 

 Transactions are illustrated, the comparisons are easily 

 made between the segments, sutures, and proportions of the- 

 cranial cavity in man gorilla, and macaque. The differences 

 between man and gorilla in this important region are truly 

 immense ; between gorilla and macaque so trifling, that in 



