410 



THE VERTEBRATE SKELETON. 



patch for articulation with the sacrum ; its outer or gluteal 

 surface is concave. The posterior part of the bone is flattened 

 below, forming the narrow iliac surface (fig. 78, A, 5). 



10- 



FIG. 78. EIGHT INNOMINATE BONE, A, or A FULL-GROWN TERRIER, B, OF 



A COLLIE PUPPY, x 1. 

 A is seen from the ventral side, B from the inner or sacral side. 



acetabulum. 8. 



thyroid foramen. 9. 



supra-iliac border of ilium. 10. 



sacral surface. 11. 



iliac surface. 12. 



acetabular border. 13. 



pubic border. 14. 



ischial border. 



ischium. 



tuberosity of ischium. 



ischial symphysis. 



pubis. 



pubic symphysis. 



cotyloid or acetabular bone. 



The ischium (fig. 78, 9) is a wide flattened bone forming 

 the posterior part of the innominate bone. It meets the 

 pubis ventrally, but is separated from it for the greater part 

 of its length by the large obturator or thyroid foramen 

 (fig. 78, 2). At its posterior end externally it bears a rather 



