Fig. 7. Dorsal view of the caudal sinuses of a small L. osseiis; the dorsal 

 walls of each being removed to show their median communication and the 

 semi-lunar valves guarding their exit into the caudal vein. Natural size. 



Fig. S. Shows distribution of a lateral artery and vein as seen from the 

 left side of a small L. tristoechiis. In this dissection the great lateral trunk 

 was removed, but its position is indicated by dotted lines, x %• 



Fig. 9. The distribution of the dorsal fin vein and artery as seen from the 

 right side of a small L. tristoecJius. All of the musculature in this region is 

 completely removed. In another specimen where these vessels were traced 

 out the artery took its origin seven or eight vertebrae cephalad of its position 

 here, and approached the basal canal of the dorsal from in front, x ^.'■2- 



Fig. 10. From a transverse section through the caudal peduncle region of a 

 90 mm. L. osseus about midway between the dorsal and the caudal fins as seen 

 from the rear (caudad) ; showing the caudal artery and vein, together with 

 the dorsal, ventral, lateral and hsemal trunks in section. Note the connection 

 between the right lateral and the right hfemal trunks. X ^■ 



Fig. 11. A portion of a transverse section .07 mm. caudad of Fig. 10. 

 Here the caudal artery and vein, together with the right hremal and the two 

 sinuses (x), are seen in section. In a section .04 mm. cephalad the right 

 sinus (x) takes its origin blindly, and the left haemal trunk is leaving the 

 haemal canal to become the left sinus (x). x 9- 



