190 



THE ELASMOBRAXCH FISHES 



of the stomach, the anterior gastro-pancreaticosplenic supplies the cardiac 

 stomach. Its gastric part divides into two branches which supply the dorsal 

 and distal halves of the cardiac stomach. The branch supplying the dorsal 

 half may anastomose with twigs from the dorsal gastric artery which in Mns- 



telus may be a derivative of the 

 anterior gastric (a.g., fig. 173b). 

 The splenic branch of the anterior 

 gastro - pancreaticosplenic leaves 

 the gastrosplenic stem near the 

 union of cardiac and pyloric limbs 

 and passes to the spleen on the 

 angle of the stomach. 



The posterior intestinal divi- 

 sion of the superior mesenteric 

 uniformly in the sharks is con- 

 tinued as the dorsal intestinal ar- 

 tery along: the dorsal side of the 

 intestine. In the rays a posterior 

 intestinal artery as such is absent, 

 for in them the superior mesen- 

 teric is a long stem which reaches 

 entirely to the valvular intestine 

 (see s.m., figs. 175 and 176). As 

 in the sharks, its continuance 

 along the dorsal side of the intes- 

 tine may be designated as the 

 dorsal intestinal artery. 



In higher vertebrates the coe- 

 liac and superior mesenteric ar- 

 teries combine into a coeliacomes- 

 enteric. This, how^ever, does not 

 occur in Elasmoln-anchs. In a ray 

 like Dasyatis (fig. 175) part of 

 the function of the superior mes- 

 enteric may be performed by the 

 coeliac, that is, the anterior gastro-pancreaticosplenic which in sharks, as a 

 branch of the superior mesenteric, arises from the anterior intestinal artery, 

 which is a derivative of the coeliac axis. 



Fig. 178. Arteries of the pectoral fin, Acanthias, 

 dorsal view. (From Erik Miiller.) 



br., bracliial artery; l.p., lateral pterygial ar- 

 tery ; m.p., median pterygial. 



INFEEIOE MESENTERIC ARTERY 



The inferior or posterior mesenteric artery {i.m., figs. 173 and 174) usually 

 arises as a single vessel, except occasionally as in Acanthias (see fig. 179) , and 

 is more or less removed from the anterior mesenteric. It supplies branches to 

 the epigonal organ or non-functional part of the sex gland in forms in which 

 such exists {Heierodontus, fig. 174, ep.; Triakis, and Mustelus antarcticus) , 



