THE SKATE. 43 



and superior mesenteric arteries (Fig. 20, d, s.m) towards 

 the left, and the wide thin-walled portal vein (Fig. 16, p) 

 between them. 



Running parallel with these vessels is also a transparent thin-walled 

 lymphatic vessel, from which many of the chief lymphatics can be 

 injected. 



94. The gall bladder (Fig. 15, g.b), a greenish or 

 yellowish transparent sac, partly imbedded in the liver 

 between its right and middle lobes. 



Fio. 15. — Raja nasuta. The gall bladder and bile ducts (half nat. 

 size). 



c.b.d, common bile duct: c.d, cystic duct : g.b, gallbladder; l.h.d, 

 left hepatic duct : r.h.d, right hepatic duct. 



XVII. Carefully dissect away the peritoneum from the 

 bile duct : make a small aperture in its wall, in- 

 troduce a blowpipe and inflate : the gall bladder 

 will be distended : trace the duct in both directions 

 and make out 



done separately : the femoral and ilio-hsemorrhoidal veins also often 

 escape being filled. In a preparation for demonstrating purposes it is 

 advisable to colour the plaster of Paris used for injecting the dorsal 

 aorta with vermilion or carmine instead of French blue. 



£ 



