112 ALLEN 



each of these veins empties directly into the right cardinal, which 

 in Scorfmnichthys runs along the ventral surface of the kidney. 

 In both male and female the right and left spermatic veins are 

 continued some little distance cephalad of the reproductive 

 organs, and empty into their respective cardinal veins, a little 

 behind the point of union of the cardinals with the jugulars to 

 form the precava. 



The caudal vein (fig. 27 ; Cau.V.) in Hexagramnios after 

 passing through the first caudal vertebra gives off an anterior 

 and a -posterior renal portal vein (fig. 27 ; Ren.P.V.) The 

 former is the principal renal portal vein ; it continues cephalad 

 along the dorsal surface of the kidney, and breaks up into 

 numerous afferent renal veins. In one specimen this vein 

 appeared to empty directly into the right cardinal vein. The 

 smaller posterior renal portal breaks up in the caudal end of the 

 kidney. One of its branches receives the vein designated as 

 the urinary bladder vein (fig. 27 ; U.Bl.V), which may to some 

 extent be analogous to the posterior mesenteric vein of Ophio- 

 don and Scorpcenichthys ; it has its source from a meshwork of 

 small veins on the rectum, which anastomose with branches of 

 intestinal vein^j^ ; passing across and along the dorsal surface 

 of the bladder from which it receives several branches, it pierces 

 the ventro-caudal end of the kidney, and gives off several 

 branches in the kidney before uniting with a branch of the 

 renal portal. The right cardinal (fig. 27 ; R.Car.V.) as in the 

 other genera arises in the extreme posterior end of the kidney, 

 and passing cephalad close to the ventral wall, unites with the 

 right jugular in the right fork of the kidney to form the right 

 precava. The veins from the caudal region of the ovaries 

 empty into a longitudinal vessel that passes between the ovaries ; 

 farther forward this vein bifurcates, one branch running along 

 the dorsal surface of the left ovary and the other along the 

 right ; both of them receiving numerous branches from the lat- 

 eral surfaces of their respective ovaries. From the right longi- 

 tudinal spermatic vein there arise an anterior and a posterior 

 branch, both of which unite with the corresponding branches 

 from the left longitudinal spermatic vein in forming the main 

 anterior and posterior spermatic veins (fig. 27, Sper.V.^,) ,^,„, 

 fo)) which empty directly into the right cardinal. 



