xiir 



PHYLUM CHORD ATA 



157 



inf.Jugv 





■which briritfs back (lie bluod froiii thu tail, running, along with the 

 caudal artciy thruugh the inlcriur arches of the vertebrie, divides 

 on entering the ab- 

 dominal cavity into 

 rioht and left nnal 

 portal veins, which 

 end in a number of 

 afferent renal veins 

 supplying the kid- 

 neys. 



The liciKdic iiortal 

 vein (A. 'port, v^ is 

 formed by the con- 

 fluence of veins de- 

 rive d f r o m t h e 

 intestine, stomach, 

 pancreas, and spleen, 

 and runs forwards to 

 enter the liver a 

 little to the right of 

 the middle line. In 

 Hemiscyllium a large 

 branch connects the 

 genital sinus with 

 the intestinal tribu- 

 taries of the hejmtic 

 portal system. The 

 blood from the liver 

 enters the sinus ven- 

 osus by two hepatic 

 sinuses placed close 

 together. 



Nervous System. 

 — The fore-brain con- 

 sists of a rounded, 

 smooth 7? r (y s c 71 c c - 

 2)haIon (Fig. 8 21, 

 V.H.) divided into 

 two lateral parts by 

 a very shallow median 

 longitudinal groove. 

 From its antero- 

 lateral region each 

 half gives off a thick 

 cord, which dilates 



into a large mass of nerve-matter, the olfactory Indh {L. ol.), closely 

 applied to the posterior surface of the corresponding olfactory 



l.borb.v 



ccuui.v 



Fk;. SiiO.— Hemiscyllium. J )i;igrammatic representation of 

 the vential amta ami affLi-ont branchial arteries, and of the 

 chief veins. idi. alimentary canal ; h,\ r.^-hw vfi afferent 

 branchial arteries ; c<i.vA. r. caudal vein ; drt. r. ductus 

 Cuvieri ; lit. heart ; lu/i. port, i: hepatic portal vein ; hep. «. 

 hej)atic sinus ; //(/. jur/. v. infei-ior jugular vein or sinus ; 

 juri. V. jufrular vein or sinus ; lat. r. lateral vein ; lir. liver ; 

 I. aoxl. ■'< left cardinal sinus ; I. poi-l. r. left renal portal vein ; 

 ncph. kidney ; /•. card. x. right cardinal sinus ; r. port. r. 

 right renal portal vein. 



