24 



ART. 4. — EKITARO NOMURA 



undergoing a few windings on the way, and after coursing on 

 the ventral side between the nerve cord and the body wall, open 

 into the ventral vessels at the posterior part of the segment. A 

 transverse commissure is often present between these commissural 

 vessels near where they unite with the ventral vessels (fig. 11). 



The above description applies to the commissures of segments 

 III- VII ; but behind the fourth segment they are confined to 

 their own segments by reason of the presence of the septa, and 

 in these segments the commissures invariably start and end near 

 the posterior septum of the segment. 



In segment VIII they are absent. 



In segment IX they undergo several convolutions around the 

 anterior sperm- sacs. 



In segment X the vessels enter the posterior sperm- sac, and 

 in fully mature specimens they also enter the anterior sperm- sacs. 



In segment XI the vessels first surround the prostate, and 

 then enter the ovisac. 



In segments XII-? XVII, in which the ovisac lies, the vessels 

 always surround it. 



In the more posterior segments the commissures run simply 

 from the dorsal to the ventral vessel. 





Fig. 15. 



L. gotoi. Diagram showing the 

 mutual connections of the blood 

 vessels in the middle part of the 

 body, dv — dorsal vessel, siv — supra- 

 intestinal vessel, int — intestine, vc — 

 ventral vessel, sp — septa, cc — ccelom- 

 ic commissure, ci — intestinal net- 

 work. 



Fig. 16. 



L. gotoi. Diagram showing the 

 courses of the integumentary vessels 

 in the posterior part of the body, 

 dv — dorsal vessel, int— intestine, vv 

 — ventral vessel, nc — ventral nerve 

 cord. 



