LYMPHATICS IN TAIL REGION, SCORP^NICHTHYS 9 



basal canal of the fin; while in the Clinocottus series the order of 

 bifurcation was: first the minor acudal artery, then the caudal 

 artery, the caudal vein, and finally the caudal lymphatic trunk. 

 With Scorpaenichthys both caudal fin veins receive numerous 

 caudal ray veins (fig. 4, C.R.V.) from the caudal rays. Their 

 arrangement, however, is not so regular as the caudal ray arteries. 

 For example, the first of the dorsal caudal ray veins (see fig. 4) 

 in addition to receiving a branch from the dorsal and ventral 

 surface of the first dorsal caudal ray collects a third branch which 

 traverses the ventral surface of the second dorsal caudal ray; 

 while the second dorsal caudal ray vein takes its source solely 

 from one stem, which passes along the dorsal surface of the sec- 

 ond dorsal caudal ray vein. These veins collect the capillary 

 networks from the fin membranes and from the rays themselves. 

 The veins arising from the intrinsic muscles of the caudal fin empty 

 separately into both lateral sides of the caudal fin veins. 



In the Clinocottus series I was unable to trace the main caudal 

 vein much beyond its branching in the basal canal of the tail, 

 and no caudal ray veins were seen unless the caudal ray canals 

 (fig. 3, C.R.T.) function both for lymphatics and veins. Pos- 

 sibly the injection method would have revealed caudal ray veins 

 emptying into the caudal fin veins. Since, the caudal ray arteries 

 and canals are distinctly visible in all the sections through the 

 rays, one could hardly claim the section method faulty for not 

 showing these vessels. 



As stated above, the caudal fin veins in a 30 mm. Phanerodon 

 lie posterior to the caudal fin arteries in traveling through the 

 basal canal of the tail. Only one caudal ray vein (fig. 11, C.R. V.) 

 was observed coming from a caudal ray. Those from the dorsal 

 half of the fin ran along the ventral side of the rays; while those 

 from the ventral half of the fin followed along the dorsal surface 

 of the rays. With the exception of the first ventral caudal ray 

 vein, none of these vessels forked ; this vein, however, divided, one 

 branch came from the dorsal side of the second ventral caudal ray, 

 and the other from the dorsal surface of the third ventral ray. 

 The vascular suj^ply for the caudal fin of a young Phanerodon 

 embryo is therefore very simple. An artery traverses one side 



