6 G. Eisen, 



within the 7"' segment'). The muscular structure of the oesophagus is 

 largely developed and very much contrasting with the intestine proper, 

 which is furnished with muscles in a much smaller degree. 



The intestine proper is divided into two distinct parts: one anterior 

 beginning in the 10"' segment, much broader, covered with minute pig- 

 mented cells, and one posterior, narrower, nearly devoid of the above 

 cells. Fig. 5 & 6. PI. I. The anterior larger part of the intestine occupies 

 generally 25 segments in fullgrown specimens. Any large flasklike cells, 

 covering the alimejitary canal like those in FhreatothrLc^ do not exist in 

 our present form. The imderside of the dissepiment betw.een the 0*'' & 

 7"' segments is entirely covered by muscular strata, all uniting in two 

 large bands, one on each side of the ventral ganglion, and with their 

 posterior ends attached to the dissepiment and integument between the 

 7*" & 8'" segments. Fig. 5 PI. I. 



The vascular system of Omerodrilus differs already at first sight 

 so considerably from that of any other known Limicolide, that it not 

 only characterizes the animal, but also places it in an isolated position 

 in the system. In other genera a separate heart is not differentiated, 

 but in Ocnerodrilus we find two large and distinct pairs, one in the 8"' 

 and one in the 1»*'' setigerous segment. Both communicate with the 

 ventral vessel. 



The forking of the dorsal vessel is however that which character- 

 izes Ocnerodrilus the most. In all other Limicoles the dorsal vessel is 

 entire, but in our present genus we find in the 7"" setigerous segment 

 two lateral branches besides the main trunk, which is continued towards 

 the cephalic lobe, all three connected with each other and with the 

 ventral vessel which is not forked, and forming, especially in the foremost 

 segments a perfect net of anastomosing bloodvessels. PI. I fig. 8. 



The other lateral vessels are of two kinds: a, gastric, partly en- 

 closed in the walls of the alimentary canal, and: 6, perigastric, free in 

 the perigastric cavity of the body. 



The former ones are plainly visible on the intestine, especially 

 when subjected to some pressure. We find of them two pair in every 

 segment: One arterior situated just under the dissepiment between the 

 two segments, and one posterior, in the first anterior (juarter of every 



') In the figure 5 PI. I. the ends of the sacks are drawn as if they were ex- 

 tending into the segments in front. That is however not the case. The dissepiment 

 betw. the 6"' & 7"* segments should be represented as more bent, in a half circle, 

 just as the sacltlike appendices themseh'cs. 



