On the anatomy Ocnkrodrilus. 7 . 



segment. Those gastric vessels seem not to be connected with the ven- 

 tral bloodvessel, but end in or on the walls of the intestine. 



Between the large gastric vessels a very minute rectilineal net of 

 vessels is seen entirely covering the intestine and oesophagus. The 

 blood itself is yellowish red, pulsating in all dorsal vessels. 



Of perigastric vessels are found one pair in each segment, close 

 to its posterior integument, or in the middle of its last quarter. They 

 are connected with the ventral vessel, and emit many secondary bran- 

 ches, which partly communicate with each other, partly with the peri- 

 gastric system of the next segment in front, partly also end in the 

 perigastric cavity. Two of those tertiary branches are considerably 

 larger than the others, and take their origin near the junction of the 

 ventral vessel and the main perigastric vessel, and project from there 

 obliquely toward the front part of the body, and communicate with the 

 perigastric vessels of the next segment. I have no doubt that those 

 perigastric vessels are homologous to the two lateral branches in the 

 7"' segment, and with the hearts in the 8"' and 1)"' segments. 



In the 6 anterior segments the jierigastric vessels form a j^erfect 

 ring, connecting the two main, and the two lateral vessels with each 

 other. All perigastric vessels emit minute secondary branches, which 

 spread in the integument of the body, here constituting the dermal 

 vascular système. Fig. 8 PI. I. 



Thus the vascular système of Oaierodrilux differs considerably 

 from that of any previously known Limkole^ but resembles that of Liim- 

 bn'ruliJu' in having gastric vessels which do not connnunicate with the 

 ventral main vessel. It also resembles Tubificidxe in having large puls- 

 ating hearts. 



The segmental organs are present in all setigerous segments ex- 

 cept in the 13"' c^ 10"'. In the former they are replaced by the oviducts, 

 and in the latter by the efferent ducts and receptacle, which both open 

 in the same segment and into the porus. The whole organ resembles 

 more that of a Limnodriius or Tubifex^ than those described as belong- 

 ing to any gemis of Lumhriculidœ . The interior opening is not sur- 

 rounded by any large brown glands, as is the case in RJii/ndielmis^ Phrea- 

 tothrix, etc., and the entire duct is devoid of all large translucent cells, 

 like those found in Rhynchelmis^) or in certain species of Lirimodrilus. 



The interior opening is situated close to the exterior one, and 

 the main body of the organ extends far up towards the dorsal part of 

 the body. PI. II Fig. 18. 



») Vejdovsky, Z. f. w. Z. Hd. XXVII. T. XX II I. 



