LYMPHATICS IN TAIL REGION, SCORP.^NICHTHYS 21 



moses with both the dorsal caudal fin lymphatic trunk and the 

 greatly enlarged next to the last neural lymphatic vessel (fig. 4, 

 C.T. (1) and Neu. T. d)), and through the latter reaches the longitu- 

 dinal neural trunk. In certain portions of the posterior dorsal fin 

 two neural lymphatic branches fuse at the base of the fin between 

 the extrinsic and intrinsic muscles, forming for a short distance 

 an analogous vessel to the lateral dorsal lymphatic trunks of the 

 anterior dorsal fin. The structure of this trunk is identical with 

 that of the ventral trunk, which will be described in the next 

 paragraph. 



Ventral subcutaneous lyrnphatic trunk. (Figs. 1, 4 and 12, 

 V.T.). — This trunk pursues a course along the ventro-median line 

 of the caudal peduncle identical with that of the dorsal trunk 

 along the dorsal side of the caudal peduncle, and like the dorsal 

 trunk it is not a continuous trunk posteriorly. In an earlier 

 paper (p. 57) its cephalic course and termination was given. In 

 front of the vent it divides into a right and left fork, which pass 

 to either side of the vent and can be traced for a short distance 

 along the bases of the anal fin, between the extrinsic and intrin- 

 sic muscles. In a like manner it arises again from two forks, 

 coming from the posterior bases of the anal fin. Immediately 

 behind the anal fin these forks unite, forming a single trunk, 

 which traverses the ventro-median line of the caudal peduncle, 

 directly beneath the skin in a tough fibrous tissue sheath that binds 

 the two great lateral muscles together. Near the base of the cau- 

 dal fin it anastomoses with both the ventral caudal fin lymphatic 

 trunk and the posterior haemal lymphatic trunk or the two last 

 haemal lymphatic trunks (fig. 4, C.T. (2) and Hce.T.a) and (2)), 

 and through the latter reach the longitudinal haemal lymphatic 

 trunk. 



A transverse section through the ventral trunk of an adult 

 Scorpaenichthys presents the appearance of a large cavity within 

 the ventral intermuscular septum, which consists of a mass of 

 fibrous tissue ; the ventral portion of which is the inner layer of the 

 skin, and here the fibers have a tendency to run in one direction 

 and to form bundles. The inner layer is endothelium, within 

 which there are but few corpuscles; the red, however, greatly 

 predominate over the white, in a ratio of about 4 to 1 . 



