On' the anatomy of Ocnerodrilus. 9. 



actly egg-cells with a conspicuous nucleus and are found nearest the 

 dissepiment. Fig. 17. PI. II. 



The efferent ducts differ from those of other Luuibriculide genera 

 in having no prostate glands, and also in opening in the same segment 

 and into the same external porus as the receptacle. This porus is si- 

 tuated as far back as in the 1(5"' segment. Fig 9. PL I. 



In Lumhrindus, Stylodrilus^ Trichodrilus and PhreatothrLr the efferent 

 ducts are confined to only two segments, in Rliynchelmis they extend 

 through five ') segments, but in Ocnerodrilus ihey are found extending 

 through 8 segments or from the middle of the 16"' to the middle of the 

 9"'. The lower and larger part of the efferent ducts seems at first sight 

 to consist of a single duct, which is divided in the 11"' segment in two 

 separate ducts, each one carrying at the end the usual funnelshaped or- 

 gan. But viewed with a high magnifying power, the apparently single 

 duct is found to consist of two different ones, which however are closely 

 grown together, and more so the nearer we approach the exterior op- 

 ening (Fig. 3). This growing together is however never perfect, as even 

 close to the external porus the two interior ciliated canals are seen to 

 be divided or separated by an etremely fine and tender membrane, in 

 which no cells are visible. Fig. 14 represents a part of the efferent 

 ducts in the 11"' segment, fig. 15 & 16 again parts nearer to, and close 

 by the exterior porus in the 16"' segment. Fig. 18 represents the porus 

 of the reproductive organs as seen in optical section, showing the jun- 

 ction of the efierent duct and the receptacle. 



No atrium can be said to exist, as the ciliated epithelium which 

 always is absent from the atrium, here extends clear down to the lower 

 end of the genital porus. The said porus is surrounded by several cir- 

 cular muscles, but no traces of prostate glands can be found. 



The first efi'erent-funnel is engaged in the dissepiment between 

 the 9"' & 10"' segments and the second or lower one in the dissepiment 

 between the 10"' & 11"' segments. In all other genera of LumhncuUdœ 

 the efferent funnels are situated nearer to the male porus, and in fact 

 always, even in Rhynchelmis^ in the segments surroimding the same. 



The ovaries are found in the ll**" segment attached to the disse- 

 jjiment between that and the 12*'' segment. Their general form is unlike 

 that of the said organs in Trichodrilus and Phreatothrir^ but resembles 

 more that of other genera, such as Lnmbricuhis and Sti/lodrilus. The 



') Vejdovsky, Z. f. w. Z. Hil. .XXMI. T. XXII. 



Nova Acta Reg. Soc. Sc. Ups. Ser. III. 



