x PRACTICAL DIRECTIONS 475 



T I inches behind the cceliac ; c, the Uenogastric artery, 

 arising close behind, and then crossing, the anterior 

 mesenteric ; and d, the small posterior mesenteric artery, 

 passing downwards to the rectal gland. 



4. The large hepatic sinus, immediately in front of the 

 liver, below the gullet : slit it open, and note the veins 

 entering it from the liver. On either side of the gullet in 

 this region along the dorsal surface of the coelome, a 

 capacious cardinal sinus will be seen : make an aperture in 

 this, and pass a seeker backwards, noting that the sinus 

 narrows into the cardinal vein, which passes along the inner 

 side of the corresponding kidney and parallel to the aorta 

 (Figs. 119 and 122). The genital (spermatic or ovarian) sinus 

 communicates with the cardinal. 



5. The lateral abdominal veins (Fig. 122, lat.}, running on 

 either side of the body just beneath the peritoneum. Cut 

 through the body-wall on one side, a short distance behind 

 the pectoral fin ; insert a cannula, directed forwards, into 

 the cut end of the lateral vein (see Fig. in), and inject. 

 The vein will then be seen running forwards as far as the 

 pectoral arch, when it turns towards the dorsal side. 



6. In the female, the united anterior ends of the oviducts, 

 and their coelomic aperture, ventral to the gullet and just 

 in front of the liver. 



IV. Taking care not to injure the anterior ends of the 

 oviducts and to leave part of the hepatic sinus in situ, 

 remove the liver, together with the stomach and intestine, 

 \\ ilhout injuring the bile-duct, cutting through the stomach 

 at its junction with the gullet and the intestine just in front 

 of the rectal gland. Wash out the portion of the enteri'c 

 canal thus removed under the tap, fill it with water, and 

 place the whole under water in a dissecting-dish. Cut away 

 portions of the wall of both stomach and intestine, and make 

 out 



1. The course of the bile-duct and pancreatic duct, and 

 their apertures into the intestine. 



2. The pyloric valve, and the spiral valve of the intestine, 

 which makes about seven or eight close turns, appearing 

 like a series of cones one within the other. 



3. The characters of the mucous membrane of the stomach 

 and intestine. 



Sketch your dissection. 

 D. Urinogenital organs. 



I. After noting again the gonads, and in the male the 

 delicate efferent ducts of the spermaries (Fig. 127, A), remove 



G G 2 



