58 ANTHROPOID APES. 



crest we may see tlie two well-developed bony lidges 

 which almost touch each other, and which indicate 

 the upper limits of the temporal muscles on either 

 side. In young animals these ridges tend down- 

 wards over the sides of the head, below the vertex 

 of the skull. Their position and direction vary 

 with the growth of the skull, and correspond with 

 that of the coronal crest. The transverse occipital 

 crest is of considerable height in the case of aged 

 and vigorous animals, and is frequently somewhat 

 concave in front, and convex at the back. The fore 

 surface of this crest is formed of the two parietal bones, 

 the hinder surface of the squamose portion of the 

 occipital bone. The lambdoidal suture is on the 

 top of this occipital crest, and in this case, as in 

 that of other mammals, including man, it unites the 

 parietal bones with those of the occiput. The point 

 of union between the coronal and occipital crests 

 divides the latter into two symmetrical lateral halves, 

 curving outwards and downwards. The hio-h, wide 

 squamose portion of the occipital bone is somewhat 

 flattened behind, or more rarely arched, while it is 

 abrupt at its base and in some degree in front. Six 

 curved lines, three on either side, opposite each 

 other, sometimes mark the limits of the attachments 

 of the cervical muscles on the head. The mastoid 

 process of tlie temporal bone is present, but Briihl 

 could find no trace of a styloid process on the skulls 

 of gorillas and chimpanzees. 



The squamous portion of the temporal bone is 

 often connected with the frontal bone by the pro- 

 cess termed Virchow's frontal process of the tern- 



