ANATOMICAL STRUCTURE OF ANTHROPOID APES. 63 



skull of which the sutures were still open, and could 

 already trace the development of the coronal crest 

 in two divisions, separated from each other by a 

 longitudinal furrow. The upper edges of these 

 divisions corresponded to the two temporal ridges, 

 which were in close proximity to each other. If the 

 animal had not died at this stage of its development, 

 it is probaljje that, with advancing growth, the two 

 divisions of the crest would have been welded into 

 one structure. Such a condition only characterizes 

 a transitory stage of development, repeated in each 

 individual. 



In the centre of the vertex of the cranium, where 

 the longitudinal crest of which we have so often 

 spoken is subsequently developed, we may often 

 observe on the sagittal suture of the cranium of 

 a young male a longitudinal swelling, which increases 

 very gradually. In the region of the two upper 

 semicircular curved lines (linese semicireulares s. 

 nuchie supremse), on the squamous occipital portion, 

 or between these and the two central cervical lines, 

 a transverse swelling is early developed ; this swell- 

 ing sometimes extends to the lambdoidal suture, 

 or, at any rate, to its neighbourhood. This bony 

 excrescence, of which the anatomical term is Torus 

 oceipitalis transversus, corresponds to the first layer 

 of the transverse occipital crest so characteristic of 

 the old male gorilla (see Fig. 15). 



In several skulls of young gorillas, in the region 

 of the coronal suture, a small, insulated, intermediate 

 bone may be observed (Virchow's os epiptericum) 

 between the squamous portion of the temporal bone 



