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fi'om ilio ])(unt of division tlie croliac aitorv (A. ear.) is 

 o-ivon off. From this artery a small vessel arises (A.hep.) 

 wliirli turns backwards and enters the liver on the pos- 

 terior surface of that org-an. Tlie two cfpliaco-mesenteric 

 tiunks then pass internally to the rielit lohe of the liver. 

 One vessel runs in the mesentery, giving" origin to 

 branches which supply the greater portion of the intestine 

 from the anus forAvards. The other courses in the mesen- 

 teric sheet connecting the liver with the duodenal 

 loop, and supplies that portion of the intestine and 

 the stomach. 



The dorsal aorta gives origin to a pair of arterial 

 trunks in each segment, Avhich supply the muscles of the 

 trunk. Towards the posterior extremity of the kidney, a 

 large median vessel — the common genital artery (A. gen.) 

 — is given oif, and passes dowuAvards through the posterior 

 portion of the kidnejv, sending small branches to the 

 kidney and suprarenal bodies. This divides into two 

 branches, one of which goes to each ovary or testis and the 

 adjacent portions of the body wall. The dorsal aorta then 

 passes backwards to the tail in the tunnel formed by the 

 haemal arches. 



With regard to the venous system, we propose to 

 describe the larger venous trunks only. All the blood 

 from the head is returned to the heart via the paired 

 superior and the unpaired inferior jugular veins. 



The Superior Jugular Veins (F. Jug.) are large thin 

 walled vessels which will have been exposed in dissecting 

 for the branchial vessels. 1'hey receive the blood from 

 the eyes and adjacent jiarts, and accompany the eye 

 muscles in the eye muscle canal, emerging from the latter 

 through the jugular foramina {f. jug. fig. 2). They then 

 run backwards on the ventral surface of the skull over the 

 dorsal extremities of the branchial vessels slightly dorsal 



