4 Gustaf Eisen, 



vessels with each other. Between these gastric vessels we find a perfect 

 net of tertiary rectilinear vessels, running in and on the layers of the 

 alimentary canal. (PL I. fig. 2. g. v. p. & g. v. s.). 



From the head backwards we therefore meet with the following 

 secondary vessels: In the first segments inclusive the 9*'' only connect- 

 ing perigastric vessels, one pair in every segment. From the lO"" segment 

 and backwards gastric vessels between which a perfect net of rectilinear 

 secondary gastric vessels. In the 30 odd last segments we find only 

 free perigastric vessels, 2 pairs in every segment, none of which is 

 connected with the ventral vessel. 



Thus the vascular system of Edipidrilwi^ however characteristic, 

 does greatly resemble the same system in Tubificidce and Lumhviculidœ. 

 The most characterizing feature is the presence of only one pair of 

 secondary vessels in every segment except the 30 last ones. In most 

 genera of the above families we generally find both gastric and periga- 

 gastric vessels in the same segment. In Eclipidrilus^ this is never the case. 



An other prominent feature is the unusual length of the peri- 

 gastric vessels in the 8"' & 9"' segments. A somewhat similar elongation 

 of the perigastric vessels is also found in Telmatodriliis ^) in the family 

 of TuhificidcB. In this genus however the perigastric vessels are confined 

 to their proper segments, performing however the same duty, viz: the 

 furnishing of blood to the sexual organs. 



The forking or imperfect feathering of the posterior perigastric 

 vessels, is also found \\i PhreatothrixYQJå.^). But in this worm, as in all 

 other genera of Tubificidce and Lumbriculidce, the ventral and dorsal 

 vessels are always connected by secondary vessels. 



The blood is redish yellow and sufficiently bright to appear through 

 the body wall. Even for the unarmed eye the ventral vessel appears 

 as a red continual streak, from which sometimes even the secondary 

 vessels are seen branching. 



The alimentary canal is extremely simple. It consists merely of 

 a simple duct, similar to that of Tubificidce, In the 5 first setigerous 

 segments the duct is pellucid, but in the following segments it is covered 

 with dark opaque glands, similar to those so often found in near related 

 families. 



The nervous system of Eclipidrilus presents no very distinct char- 

 acteristics. The two ventral nerve cords, which together form the ventral 



») Bihang. K. Svenska Vet.Akad. Handl. Bel. 5. N. 16. pag. 8. 

 -) Zeitschr. f. W. Zoologie. Bd. XXVII. pag. 541 etc. 



