LYMPHATICS IN TAIL REGION, SCORP^NICHTHYS 5 



onic neural arteries and if so should be considered as the posterior 

 neural arteries instead of the hypural arteries. In the Clinocottus 

 series the posterior neural artery was noticed, but the hypurals 

 were not observed. 



The course of the caudal fin arteries (figs. 4-6, and 8, C.F.A.' 

 and C.F.A.") is either dorsad or ventrad in the basal canal of the 

 caudal fin.^ In the transverse series of Clinocottus the division 

 of the caudal artery into the caudal fin arteries was clearly seen, 

 and in fig. 11 the forking of the caudal artery in a 30 mm. Phane 

 rodon embryo is shown. In Scorpaenichthys, Clinocottus, and 

 Phanerodon a small branch, the caudal fin ray artery (figs. 4, 8, 

 and 11, C.R.A.) is given off to the center of each ray. In Scor- 

 paenichthys and Clinocottus after continuing caudad a short 

 distance in the center of a ray this artery forks, one branch passing 

 along the dorsal surface of the ray and the other along the ven- 

 tral surface, each giving off a network, to the ray and to the fin 

 ray membrane. In the 30 mm. Phanerodon embryo (fig. 11) the 

 first ventral caudal ray artery forked as they all do in Scorpaen- 

 ichthys, but the remaining ones did not bifurcate within the rays; 

 those from the dorsal half of the fin traverse the dorsal surfaces of 

 the rays, and those from the ventral half of the fin, excepting the 

 first, pass along the ventral surfaces of the rays. In the living 

 Phanerodon embryo the red corpuscles could be clearly seen leav- 

 ing these arteries to enter a network of capillaries in the fin njem- 

 brane, and become collected on the opposite side by the caudal 

 ray vein. 



Minor caudal artery. (Figs. 5-8, 10, and 12, C.A.d)). — In the 

 caudal peduncle region of Scorpaenichthys and in all sections of 

 Clinocottus this vessel was found running parallel with the caudal 

 artery, sometimes lying to the side, and again below it. At fre- 

 quent intervals this artery gives off branches (fig. 10, C.A' .(d), 

 which cross the lower surface of the caudal artery. Often these 

 branches have as great a caliber as the main stem, and so far as 



1 The basal canal of the caudal fin is a canal formed at the base of the caudal 

 fin at the point where the two halves of the caudal rays separate to become attached 

 to the hypural bones. This canal would therefore pass dorso-ventrad through the 

 proximal ends of the caudal rays. 



