10 WILLIAM F. ALLEN 



of a ray, while a vein follows along the opposite side of the ad- 

 jacent ray. In the membrane connecting these two rays there 

 is a network of capillaries, through which one could readily trace 

 corpuscles going from the caudal ray arteries to the caudal ray 



veins. 



Vogt in Salmo, Hyrtl in Esox ( = Lucius) and Leuciscus, Emery 

 in Fierasfer, Parker in Mustelus, Hopkins in Amia ( =Amiatus), 

 and Vogt and Yung in Perca did not trace the caudal vein further 

 caudal than the last vertebra, that is to the caudal sinus. Jones . 

 (p. 676) describes the great vein in the tail of the eel as being formed 

 from two branches, a larger and a smaller. The larger stem is 

 said to receive the venous radicals from the terminal parts of the 

 tail; while the smaller stem collects the venous radicals from the 

 dorsal part of the tail, and near the junction with the former it 

 receives the caudal heart. Sappey (p. 46; pi. xi, fig. 6 and pi. 

 xii, fig. 3) finds that the caudal vein in the carp and pike arises 

 from a dorsal or superior and a ventral or inferior branch in the 

 base of the fin. At the level of the last vertebra they unite to 

 again divide into a right and left branches, which reunite at the 

 end of the last vertebra in forming the caudal vein. Shortly 

 before anastomosing, each of the above branches are said to re- 

 ceive a papilla from the lateral lymphatic trunk. According 

 to McKenzie the venous system of Amiurus catus takes its origin 

 in the tail from two vessels of unequal size. Silvester (p. 109) 

 describes and figures the caudal vein in the tile-fish as having 

 its source from two branches from the caudal fin. Favaro in 

 numerous Teleosts notes practically the same arrangement as 

 described above for Scorpa^nichthys. In most species he rep- 

 resents the caudal vein as beginning as a sinus, sinus venosus 

 caudalis, under the last vertera, which not only receives the vein 

 from the tail, but also the caudal lymphatic sinus, ventriculus 

 cordis caudalis. 



Intersegmental or intercostal vessels. (Figs. 4 and 4a, Neu.A., 

 Neu.V.yHcB.A., and //ce.F.; figs. 9 and 10, Neu. andL.A.,Neu.and 

 L.V .,L.A.,L.V .,H(]e.A.,2iTid Hce.V.). — Apparently these blood ves- 

 sels are practically the same in all species of Ganoids and Teleosts. 

 They are destined to supply the body musculature, the vertebral 



