30 WILLIAM F. ALLEN 



tutliiial neural trunk is therefore cephalad, where it is discharged 

 into the jugular veins after the manner described in an earlier 

 paper (p]). 59-61). 



A trans\Trse section through the longitudinal neural lymphatic 

 trunk of Clinocottus shows this trunk to more than ecjual the size 

 of the myelon or spinal cord. It is composed of fibrous tissue and 

 lined with endothelium, and strange to say contained very few 

 corpuscles. In a representative section but two were noted and 

 they were red. 



Throughout its entire course the longitudinal neural lymphatic 

 trunk receives a neural lymphatic vessel (fig. la, Neu.T.) opposite 

 each centrum, that is, one for each segment. It should be recalled 

 in this connection that but one neural artery or vein was found 

 for every two segments, the arteries alternating with the veins. 

 Consequently^ then, since these neural lymphatic vessels run par- 

 allel, but distal, to the blood vessels in their course along the neural 

 spines, each alternate neural lymphatic vessel would follow a neu- 

 ral artery, and every intermediate alternate neural lymphatic 

 vessel would follow a neural vein. There are, however, a few 

 exce])tions to this plan. Tracing a neural lymphatic vessel dor- 

 sad, one sees it leave the apex of the neural spine with the cor- 

 responding blood vessel to cross the depressor and levator muscles 

 of the dorsal rays, and at this level it sends off a cephalic branch 

 to anastomose with the next neural lymphatic vessel, thus form- 

 ing a sort of irregular longitudinal lymphatic trunk (represented in 

 fig. 4 a, but not lettered) homologous to a similar secondary dorsal 

 lymphatic trunk described by Trois in Pleuronectes and by Sappey 

 for Lucius lucius. The neural lymphatic vessel proper continues 

 dorsad with the corresponding blood vessel between the levator 

 and the next dei)ressor dorsal ray muscles to the extrinsic mus- 

 cles of the fin. where it bifurcates with the corresponding blood 

 vessel between the extrinsic and intrinsic muscles. Sometimes 

 two of these branches from adjacent neural vessels anastomose, 

 forming a continuous longitudinal vessel for a short distance, 

 which is analogous to the lateral dorsal lymphatic trunks de- 

 scribed in an earlier paper (p. 55) for the anterior dorsal fin. These 

 forks of the neural vessel collect the dorsal ray lymphatic canals 



