CIRCULATORY ORGANS. 



297 



tion. Connected with the carotid arteries are the carotid glands (fig. 304). In 

 the larval stage each consists of a network of blood-vessels a rete mirabile 

 between the afferent branchial and the carotid artery, but in the adult this degener- 



FIG. 301. 



FIG. 302. 



ates into a small muscular organ containing sympathetic cells (p. 165), at the 

 base of the carotid. 



The postcava is well developed and the epigastric veins unite to form an anterior 



