210 



ESSENTIALS OF ZOOLOGY 



the median line posteriorly. The entrance to the pulmo- 

 cutaneous arteries is just in front of the anterior semilunar 

 valves and to the left of the longitudinal valve. Beyond the 

 conus a short ventral aorta branches into the systemic and 

 carotid arteries. 



The short ventral aorta, or bulbus aortae, carries the three 

 arches forward, dividing into right and left branches. Each 



Int. car. Lingual 



Ext. jug. 



Ling. Int. jug. 

 Md. / Subcl 

 ' 



Carotid 



Cut. a. 



Vert. a. 



Brack, a. 



Pulmon. a. 



Ventricle 



Aortic arch 



Coel.-mes. a. 



Hep. a. 



Oast. a. 



Intest. a. 



Eenal a. 



Hypogast. a. 



Iliac a. ~Tff 



Innom. v. 



'rack. v. 



Mus. cut. v. 

 Ant. vena cava 

 Pulmon. v. 

 Sinus venosus 



Cardiac v. 

 Hepatic v. 

 Hep. port. v. 

 Post, vena cava 



Abdom. v. 

 Eenal v. 



Renal portals 



Pelvic v. 

 Sciatic v. 



Femoral v. 



FIG. 106. Diagrams]of arterial and venous systems from the ventral aspect. 



branch is made up of the pulmo- cutaneous, systemic, and 

 carotid arteries, and these part company at about the same 

 level. The pulmo- cutaneous divides into the pulmonary 

 artery, which is directed to the outer aspect of the lung, and the 

 cutaneous artery, which is distributed over a wide area of the 

 skin of the back and head. 



The two systemic vessels form an arch around the 

 oesophagus and unite to form the dorsal aorta. The aortic 

 arch supplies the larynx and oesophagus, and each gives off a 

 vertebral artery to the muscles of the body wall and to the spinal 



