322 THE PELVIC GIRDLE. [CHAP. 



tuberosities are large, and have on the middle of their outer 

 side a well-marked conical process, directed outwards, and 

 very characteristic of this group of animals. 



In the Giraffe the pelvis is shorter than in most of the 

 other Pecora ; the upper ends of the ilia are more ex- 

 panded, the thyroid foramen is nearly circular, and the 

 supra-acetabular fossa is almost obsolete. 



These characters are still more strongly marked in the 

 Camels ; while, on the other hand, in the Pigs the pelvis is 

 elongated, and much resembles that of the Pecora, but the 

 supra-acetabular fossa is wanting. 



In the Perissodactylct) the ilia are widely expanded above, 

 but much contracted on approaching the acetabulum. The 

 ischia are less elongated than in the Pecora, and the thy- 

 roid foramen is more circular. 



The Elephant has a very peculiar pelvis, the form of the 

 ilium and the arrangement of its surfaces somewhat recalling 



t_> o 



those of the human pelvis. The supra-iliac border or crest 

 is greatly extended and curves outwards and downwards. 

 The sacral surface of the ilium is narrow, and scarcely rises 

 above the attachment to the sacrum. The iliac and gluteal 

 surfaces are widely expanded, especially at the upper part 

 and, the pelvis being set nearly vertically to the vertebral 

 column, they face almost directly forwards and backwards. 

 The outer or acetabular border is short and deeply hollowed. 

 The pubic and ischial portions are comparatively small, the 

 latter being very little produced backwards beyond the 

 symphysis. 



In the SIRENIA, the pelvis is extremely rudimentary, being 

 composed, in the Dugong, of two slender, elongated bones 

 on each side, placed end to end, and commonly ankylosing 

 together. The upper one, which represents the ilium, is 

 connected by a ligament with the end of the transverse 



