66 ANTHROPOID APES. 



the skeleton of the triiuk there are seven cervical, 

 thirteen dorsal, and four lumbar vertebrae, thirteen 

 ribs, and, even in aged animals, a sternum composed 

 of several pieces of bone. The cervical vertebrae 

 display long spinous processes, which are most 

 strongly developed between the fourth and seventh 

 vertebrae. The extremities of this colossal struc- 

 ture, combined with the elevation of the occipital 

 region, present a convex outline when seen from 

 behind. This structure provides the point of inser- 

 tion and support for the powerful cushion of cervical 

 muscles. The dorsal vertebrae, which increase in 

 height, width, and depth as they stand lower on the 

 column, taper, and are keel-shaped at their junction 

 with the cervical vertebnB. The central parts of the 

 widely arched ribs, which are thirteen or sometimes 

 fourtten in number, are very thick and powerful in 

 the aged male. Only seven pairs of ribs are attached 

 by the costal cartilages to the sternum, and two 

 other costal cartilages are in proximity with them. 

 The other cartilages are only rudimentary, and the 

 terminations in the muscular system of the belly 

 are free. There are, indeed, variations from the type 

 here established, and from ten to eleven ribs are 

 sometimes attached to the sternum by thread-like 

 strips of ligament or cartilage. 



The formation of the pelvic girdle in this animal 

 is of special interest. The chief parts of this por- 

 tion of the skeleton — that is, the hip, pelvic, or 

 innominate bones — are high, tapering in their lower 

 part, and broad and flat above, where they terminate 

 in the crest of the ilium, which describes a quarter 



