G4 William F. Allen 



ventral or the caudal trunk as Hopkins describes for Amiatus; on the 

 other hand, the caudal trunk empties directly into one of the caudal 

 sinuses. 



Hcemal Trunks (Figs. 2-4, 10-12 and 20, Hx. T. or E. and L. Hse. 

 T.). — In Lepisosteiis two such longitudinal trunks traverse the hgemal 

 canal. Their position is perhaps best portra3-ed in a transverse section, 

 as, for example, in Fig. 10; here, on either side of the caudal artery, a 

 little above the level of the caudal vein, are the right and left haemal 

 trunks (E. and L. Hse. T.), A comparison of Figs. 20 with 22, shows 

 us that in a 90 mm. L. osseus the size and structure of the caudal vein 

 and the hgemal trunks are almost identical. Both consist of a single 

 laj-er of endothelium (End.), and contain but few corpuscles, while the 

 caudal artery (C. A.) had an additional muscular layer, and was filled 

 with corpuscles. As previously stated, in the specimen from which Fig. 

 10 was taken, there was a connecting trunk (c) between the right 

 lateral and the right ha3mal trunks. This communication was not 

 observed on the opposite side or in any of the gross dissections. Its 

 position in this specimen is some little distance cephalad of the point 

 where the haemal trunk leaves the haemal canal to empty into sinus (x). 

 Ordinarily, as shown in Figs. 2 and 3, the hasmal trunks leave the 

 hsemal canal opposite the point where the lateral trunks bend mesad, 

 and the two unite on the ventro-lateral surface of the vertebral column 

 in what has been described as sinus (x) ; but in some instances, as in 

 Fig. 1, which is the opposite side of the same specimen as Fig. 2. and 

 on both sides of the 90 mm. L. osseus series, they leave the hasmal canal 

 first, and form or empty into sinus (x), before the lateral trunk bends 

 inward to join sinus (x). In Lepisosteus no hernial or intercostal 

 vessels were found connecting the haemal with the ventral trunks, as is 

 the case in the Teleosts. Since the lymphatics of the viscera have not 

 been studied, the anterior termination of the hsemal trunks has not 

 been traced out, but the natural supposition is that they would end in 

 an abdominal sinus, situated either below the kidney or between the 

 kidney and the vertebral column. 



With the Teleosts, Trois (op. cH., p. 11 and Fig. 4, A.) finds in 

 LopJiius, that what he terms as the ironclii linfatici spinall inferiori 

 travels along in the haemal canal and collects the intercostal vessels. In 

 Fig. 4 Trois portrays this trunk as anastomosing at the base of the tail 

 with the superior spinal, the dorsal and the ventral lymphatic trunks, 

 Le tronc sous-vertebral of the pike is briefly set forth by Sappey {op. 



