THE SKATE. 51 



loi. The superior mesenteric artery (Fig. 20, s.m) 

 entering the abdominal cavity parallel with, and a little 

 posterior to the cceliac. 



It divides into two main branches, one of which supplies the intestine 

 (i), the other the pancreas (fn) and spleen (spl). The rectum is 

 mainly supplied by the small inferior mesenteric artery (§ 157, Fig. 

 20, i.m), which passes directly from the aorta to the rectal gland. 



Fig. 16. — Raja nasuta. The portal vein (one-third nat. size). 

 du, duodenal vein : g, gastric vein : i, intestinal vein : p, main trunk 

 of portal vein : /«, pancreatic veins : j//, splenic vein. 



102. The ramifications of the gastric branch of the 

 pneumogastric nerve on the walls of the stomach (see 

 § 214). 



XX. Turn the liver into its natural position again, and 

 remove just sufficient of the shoulder girdle to 

 bring into view 



103. The hepatic sinus (Fig. 17, k.s), a large transverse 

 vessel, lying across the ventral surface of the oesophagus, 

 immediately in front of the anterior border of the liver : it 

 receives the hepatic veins by which the blood is returned 

 from the liver. 



104. The anterior extremities of the oviducts (Fig. 19, 

 fl.t) in the female, or the rudimentary pronephric ducts 



