VASCULAR SYSTEM 



i'3 



From the efferent vessel of the hyoid arch springs also a posterior 

 carotid (internal carotid), which gives off a branch to the orbit, and 

 piercing the base of the skull, enters the pituitary depression of the 



Vs.v. 



Vxau. 



Vs, 



V.ca» 



Vcp. 



V.ca* 



V.caui. 



Fig. 



Diagrams of the development of the Venous System in the Selachian. (After Rabl and 

 Hochstetter, from Hertwig's Handbuch.) Six stages. V.v, vitelline vein running into the left 

 omphalo-mesenteric ; V.si, subintestinal vein ; V.eau, caudal vein ; V.ca, anterior cardinal vein ; 

 V.cp, posterior cardinal vein ; V.sp, vein of spiral valve ; V.cl, external jugular vein ; Vs, sub- 

 clavian vein ; Vir, interrenal vein. 



cranial cavity. It joins the cerebral artery of the opposite side. 

 Segmental parietal vessels are given off by the aorta, and branches 

 to the limbs and viscera. Among the latter the coeliaco-mesenteric, 

 the coeliac, the lieno- gastric, the anterior, and the posterior 

 mesenteries are the most important. 



