12 



the majority of specimens; the anterior cardinals opening into the 

 anterior ends of the posterior cardinals in about six out of ten cases. 



A large cavity, the hepatic sinus, exists in the anterior end of the 

 liver just posterior to the suspensory ligament. Cut into the liver 

 at this point until the sinus is found, open it, and observe the large 

 hepatic veins bringing blood into it from the liver, as well as its 

 communication with the sinus venosus. 



Trace all veins by passing a flexible probe or guarded bristle 

 along them and then opening the vein with the probe as a guide. 

 All smaller vessels emptying into those described should be noted. 



The lateral veins pass forward to the posterior edge of the pec- 

 toral girdle, bend sharply dorsad, and enter the lateral extremities 

 of the ducti cuvierii. Open a lateral vein near the anterior end and 

 trace it toward the heart. The right and left lateral veins are joined 

 by a vein passing along the ventral bar of the pectoral girdle. Open 

 the lateral veins at a point about two inches in front of the pelvic 

 girdle and trace the veins backward as far as they can be followed. 

 The blood from the pelvic fins enters the lateral vein through the 

 femoral vein. The lateral veins finally unite back of the cloaca. 



Just before the lateral vein enters the ductus cuvierius it is joined 

 by a large coracoid vein which runs dorsad and posteriorly along 

 the posterior edge of the pectoral arch. Follow its course. It re- 

 ceives a good-sized pectoral vein from the pectoral fin, and some- 

 times several smaller veins from the same region. Traced dorsad it 

 is found to open into a large blood sinus above the liver and oesoph- 

 agus, the cardinal sinus. 



In Eugaleus this connecting vein between the lateral vein and the cardinal 

 sinus is wanting, the pectoral vein opening directly into the lateral. 



The ventral cutaneous vein, which runs along the ventral mid- 

 line of the body wall, should be followed; anteriorly it joins the 

 vessel uniting the two laterals; posteriorly it divides at the pelvic 

 arch and anastomoses with the laterals. 



Pass a bristle from the sinus venosus into one of the posterior 

 cardinal veins and trace the vein backward between the kidneys as 

 far as possible. Open both posterior cardinals in this way, washing 

 them out and observing that they receive blood from the kidneys by 

 a series of renal veins, and that they are separate in their posterior 

 parts, but communicate with each other anteriorly, where they are 

 greatly expanded; the communicating portions and coincident en- 

 largement forming the cardinal sinus. The anterior portion of the 

 cardinal vein receives ovarian or spermatic veins from the female 

 or male gonad, anterior oviducal veins from the anterior part of 

 the oviduct, and segmental veins from the corresponding region of 

 the body wall. There sometimes is more than a single opening from 

 the posterior cardinal vein into the cuvierian duct. 



Cut across the tail an inch behind the cloaca. Two vessels lie 

 in the cartilaginous arch below the centra of the vertebrae; the 

 dorsal of the two is the caudal artery, the ventral one is the caudal 

 vein. Follow the vein forward. Dorsal to the cloaca it divides into 

 two, which should be followed along the dorsal surfaces of the kid- 

 neys. These are the renal portal veins, conveying blood to the kid- 

 neys. Besides collecting the blood of the tail the renal portals also 

 receive the posterior oviducal and segmental veins. They pass into 

 the capillaries of the kidneys. 



The inferior jugular vein opens into the medial end of the cuvier- 

 ian duct. Trace it forward along the ventral ends of the gill-pouches; 

 it receives vessels from the arches and finally joins the hyoidean 



