LYMPHATICS IN TAIL REGION", SCORP^NICHTHYS 15 



detail later on, the lymphatics came into close touch with the 

 caudal vein, but did not anastomose. Furthermore an injection 

 of the longitudinal neural trunk often fills the caudal vein, and 

 conversely an injection of either the caudal artery or vein often 

 fills the entire lymphatic system. These occurrences I attribute 

 to an extravasation of the injection mass through the thin walls 

 separating these vessels rather than to a direct communication. 



SUBCUTANEOUS SYSTEM 



Lateral subcutaneous lymphatic trunks. (Figs. 1-2, 4-7, and 12, 

 L.T.). — As in other fishes these two trunks in Ophiodon, Scor- 

 psenichthys, and Clinocottus travel parallel with the lateral line, 

 directly within the skin, in the tough connective tissue sheath 

 that binds the dorsal half of the great lateral muscle to the ventral 

 portion. Its position is clearly portrayed in fig. 12, L. 7". A 

 transverse section of this canal in an adult Scorpaenichthys shows 

 its walls to be composed mostly of fibrous tissue, containing a few 

 smooth muscle fibers, and a peculiar papilla-like endothelial lin- 

 ing. Furthermore in consideration of the enoromous caliber of 

 this trunk it contained relatively very few corpuscles; strange to 

 say the red greatly outnumbered the white, the ratio in the field 

 examined being 26 to 4. The anterior termination of this trunk 

 was given in detail in an earlier paper (p. 51). When about 

 opposite the last vertebra its course becomes deeper (region drawn 

 in outline in figs. 1 and 2), and here it receives or is continuous 

 with a posterior lateral trunk or a posterior portion of the lateral 

 trunk, resulting in the formation of the profundus lateral trunk 

 or the profundus portion of the lateral trunk, which passes mesad 

 to unite with its fellow trunk forming the longitudinal neural 

 lymphatic trunk. 



tudinal neural and the lateral lymphatic trunks discharged their contents into the 

 right and left forks of the caudal vein. The cause of this error was due to the fact 

 that before a careful study of the tail region had been made, the posterior neural 

 vein was taken to be a lymphatic vessel, and in crossing under the posterior por- 

 tion of the lateral lymphatic trunk close to its union with the anterior portion 

 it was thought to anastomose with the former. 



