170 



ESSENTIALS OP ZOOLOGY 



ventricle has a smaller cavity, and opens in turn into the conus 

 arteriosus. The conus is furnished internally with three rows 

 of five pocket valves, or semilunar valves, and it conducts the 

 blood into the ventral aorta. 



Inf. jug. v. 

 Jugular v. 



Ventral aorta 



Conus arter. 



Ventricle 



Auricle 



Sinus venosus 



Precaval sinus 



Hepatic sinus 



Brachial v. 

 Hep. port. v. 



Gastric v. 



Intestinal v. 

 Post. card. v. 



Haemorrhoidal v. 



Femoral v. 



Iliac a. ' 



Caudal v. 



Hyoid a. 

 'arotid a. 



ff. branch, a. 



'audal a. 



FIG. 87. Kaia. Diagram of the adult circulation, lateral view. 



The ventral aorta runs forward in the floor of the mouth 

 below the basal elements of the branchial arches. It gives 

 off near its origin a pair of posterior innominate arteries, each 

 of which divides into three afferent branchials; and distally 

 it divides into a pair of anterior innominate arteries, each of 

 which splits into two afferent branchials. These afferent 



