94 



ALLEN 



L.Ven.F.V.) instead of uniting with the right ventral fin vein 

 to form the right ventral vein, forms the principal venous sup- 

 ply for the left ventral vein. 



In Hexagrammos and Scorpcetit'chtys the ventral veins are 

 essentially the same as the last case described under Ophi'odon ; 

 namely, the 2 ventral veins are of equal size, receiving their 

 venous supply from the right and left sides respectively. In 

 Scor;pcBnichthys, however, the right and left ventral fin veins do 

 not leave the ventral fin ray canal with the artery from the last 

 ray, as is the case with Ophiodoii and Hexagrammos^ but may 

 leave the canal between any 2 rays, usually, between different 

 rays in the 2 different fins. In Sebastodes these 2 veins are of 

 equal size, but another condition is introduced. The 2 ventral 

 fin veins leave the ventral fin canal with their respective 

 arteries, anastomose, and the common trunk thus formed passes 

 cephalad parallel with the ventral artery, between the two pelvic 

 bones, and usually empties into the left ventral vein. 



5. Subclavian Veins. 



In Ophiodon there are 3 subclavian veins, returning the 

 venous blood from the region of the pectoral arch. Two of 

 these, coming from the outer or abductor muscles, unite in 

 forming the subclavian sinus which empties into the sinus veno- 

 sus in front of the precava, while the third one coming from 

 the rays and the inner or adductor muscles, pierces the anterior 

 fork of the kidney. This vessel does not empty directly into 

 the cardinal trunk, but first breaks up into smaller vessels, 

 which reach the cardinal through the renal veins. 



Internal Subclavian or Subclavian VcinSf^^^ (PI. II, fig. 14; 

 Sub.V.^,)). — The vessel thus designated, in the main, cor- 

 responds with the internal subclavian artery. It receives its 

 supply in part from the pectoral rays, and in part from the ad- 

 ductor muscles, situated on the inner side of the pectoral arch. 

 This vessel has its origin from a dorsal and a ventral pectoral 

 fin vein, which unite in the pectoral ray canal, thus forming a 

 continuous vessel, which runs along behind the corresponding 

 pectoral fin artery. Within this canal it receives a small vein 

 returning the venous blood from each ray. In no 2 specimens 



