DISTRIBUTION OF SUBCUTANEOUS VESSELS IN GANOIDS 87 



According to Sappey the chylous vessels terminate in the 

 ductus Curveri through a right and left trunk (PI. VII, Fig. 5, 

 7), the openings being guarded by valves. 



Sappey (p. 32) describes a lace-like lymphatic network aris- 

 ing from the heart, especially from the ventricle and bulbus, 

 which is collected by two trunks (PI. II, Fig. 3, 3) that termi- 

 nate in the sinus of Curver. It should be noted that these two 

 vessels correspond identically with what Parker (20, p. 720) 

 describes and figures (PL 34, Fig. 4, Cor. V.) as the coronary 

 veins. 



In the rays Sappey finds numerous muscular bands encircling 

 the lymphatics, not only of the viscera as described by Leydig, 

 but also in all parts of the body. Aside from the digestive 

 tract he figures them from the subcutaneous and intermuscular 

 vessels of pectoral, from the abdominal and thoracic networks, 

 and from the networks of the ventral fin and lumbar regions. 

 When he first discovered them in 1870 he supposed that they 

 were characteristic of the lymphatics of all fish, but later found 

 them only in the rays. Sappey attributes a double role to these 

 so-called lymphatic hearts, by contracting they would cause a 

 peristaltic movement in these vessels, and to a certain extent 

 would also take the place of valves. 



After considering the lateral line system and the blood vessels 

 of Squalus Sappey takes up (pp. 37-40 and PI. X) the distri- 

 bution of the lymphatic system. On each side of the body he 

 finds two lateral lymphatic trunks, superior and inferior in posi- 

 tion. The former (Fig. 3, 2) extends from the tail to the head, 

 a little below the lateral line. In the tail region it forms a sort 

 of fibrous sinus that empties into the caudal vein ; while an- 

 teriorly it ends with the inferior trunk in a sinus or confluent 

 (Fig. i, 25), which opens into the precava, near its origin. The 

 inferior lateral trunk (Fig. 3, n) is a subcutaneous vessel, 

 traversing in a median line from the tail to the head, where it 

 blends with the superior trunk in forming a single vessel, which 

 terminates in the cephalic sinus mentioned above. It should 

 not be confounded with the corresponding vein, which is more 

 profundus, being distinctly submuscular. Sappey states that 

 the inferior trunk is sometimes absent. A median dorsal trunk 



