VEINS 



331 



they do not take the place of capillaries as well as veins in the 

 circulation, but are merely enlarged parts of the veins. The blood 

 from the liver returns direct to the sinus venosus by two hepatic 

 sinuses which enter its hinder side. The rest of the blood is 



iK-- 



FiG. 250. — A diagram of the venous system of the dogfish. The system is seen 

 from the ventral surface ; the heart, except for the sinus venosus, has been 

 removed, and some of the vessels are shown on one side only. 



a /:.$., Anterior cardinal (or internal jugular) sinus ; bra.s., brachial sinus ; c.v., caudal vein ; J.C.. ductus 

 Cuvieri, or precaval sinus ; d.l.s., deep lateral (abdominal) sinus ; c.j.s.. external or inferior jugular 

 sinus ; h.p.v., hepatic portal vein ; h.s., hepatic sinus ; hy.s., hyoidean sinus ; i.o.s., interorbital sinus ; 

 U.S., iliac sinus ; int., intestine ; k., kidnev ; Ir., liver ; n.s., nasal sinus ; or.s., orbital sinus ; p.c.s., 

 posterior cardinal sinus ; r.p.v., renal portal vein ; s.v., sinus venosus ; scl.s., subclavian sinus ; sub.c.s., 

 subscapular sinus ; sup.l.s., superficial lateral sinus. 



