CLASS AMPHIBIA 



521 



Each side of dorsal part of the girdle is composed of a large flat 

 bone, the suprascapula, which curves ventrally and joins the scapula, 

 narrowing as it does so. From the ventro-anterior end of the scapula 

 two bones extend to the midventral line of the body and would meet 

 their fellows from the opposite side except that the narrow epicora- 

 coid cartilage intervenes. The anterior of these two bars is the 

 clavicle and the posterior one the coracoid. At the junction of cora- 

 coid and scapula a depression is formed, known as the glenoid fossa, 

 into which the forelimb articulates. The ventral sternum is separated 



^j-^y -^ Lpisternum 



s- — Omosbernum 



Fig. 282. — Diagram of the ventral view of the pectoral girdle of Rana catesbelana, 



natural position. 



into two portions by the pectoral girdle. The anterior portion is com- 

 posed of a bone, the omosternum, to which is attached anteriorly a 

 rounded plate of cartilage, the episternum. The posterior portion is 

 composed of a bone, the sternum proper (mesosternum), and a round- 

 ed cartilage, the xiphisternum, which has a notch at its posterior mar- 

 gin through which the abdominal vein runs as it leaves the body wall. 

 The pelvic girdle furnishes a place of attachment and support for 

 the hindlimbs. Each half of the pelvic girdle is composed of three 

 bones, the ilium, ischium, and piibis. The more slender ilium is at- 



