THE AETEEIES 



29 



iii. A cardiac vein, from a network of vessels on 

 the truncus arteriosus. 



y^ 2. The hepatic portal vein is a wide vein which runs 

 in the mesentery and joins the anterior abdo- 

 minal vein at its point of division into right and 

 left branches ; giving off, before doing so, a branch 

 to the left lobe of the liver. It carries to the 

 liver the blood from the walls of the alimentary 

 canal, and is formed by the union of the follow- 

 ing veins : 



i. The gastric vein, from the stomach. 



ii. Intestinal veins, from the whole length of the 

 intestine, both small and large. 



iii. The splenic vein, from the spleen : this usually 

 joins one of the intestinal veins. 



C. The Arteries. 



I'"iG. 5. — Diagrammatic figure of the arterial system of the male 

 frog, from the right side. 



a, stomach ; 6, nostril ; c, small intestine ; c.a, ^carotid artery ; 

 g.p". r;^rnti^ g1p.nd : c.7n, c oeliacQ mesenteric arte r y ; c.n. cutaneous 

 artery ; d, large intestine ;' ^ ^, ^'^'''inil ^"^^^ ; f, tumm- ; A, spleen ;^ 

 h.a, hepatic artery ; i, right lung ; i.a, imgual artery ; m, testis ; 

 o, kidney;' o.a, jj gcipito-vertebral artery '; p. a, pulmonary artery ; 

 r, pelvic girdle ; j sternum : s.a. subclavian artery ; s.c, sciatic artery;' 

 t, tongue ; t.a, fpint-uc arigrincng ; u.a, unnogenital arteiies ; v, ven- 

 tricle ; 1, carotid arch ; 2, systemic arch'~ 0, pulillU-tlUiailnuusi arch. 



