848 CONTRIBUTION TO AUSTRALIAN OLIGOCHjETA, II., 



glands. A canal passes forwards from the mass of these pepto- 

 nephridia to open into the buccal cavity. 



Nephridia. — Mention of glands in connection with the alimen- 

 tary canal has already been made, and these were regarded as 

 modified nephridia. The first pair of true nephridia occurs in 

 segment ix. No nephridia can be seen in segments x.-xiii. The 

 nephridiopore is situated about the middle of each segment con- 

 taining a nephridium, immediately anterior to the ventral cbsetse 

 between the anterior two-thirds and the posterior third of the 

 distance separating the ventral seta from the anterior margin of 

 the segment. The pore is very distinct, and leads into a flask- 

 shaped bladder. The wall of this receptacle consists of polygonal 

 cells whose limits are clearly made out, the nuclei taking a dense 

 stain with hematoxylin. About eight of these cells would be 

 cut by a section passing lengthwise through the bladder. The 

 body of the nephridium extends up as far as the level of the 

 ventral margin of the alimentary canal. The funnel is distinct, 

 opening into the segment anterior to that containing the body of 

 the nephridium. After leaving the funnel, the tube passes 

 upwards parallel to the septum and then becomes twisted on 

 itself spirally. This mass appears as a hump reaching as high as 

 the alimentary canal. The first portion of the tube is intra- 

 cellular, its wall being formed by a linear arrangement of cells 

 with very granular protoplasm, their nuclei only representing 

 cellular elements. Towards the top of the spiral loop or hump 

 the cells, through which the tubule passes, have their cytoplasm 

 not granular, but with a radial striation not unlike that of 

 Hirudinean or Oligochsete muscle-cells. After again reaching the 

 level at which the funnel lies, the nephridial tube passes into the 

 bladder, to open on the exterior at the nephridiopore. The manner 

 of folding of the nephridial tube on itself is such that, in section, 

 the nephridium appears to have an arborescent form, nephridial 

 cells alternating on either side of a main stem. 



Reproductive organs. — There are present in the immature 

 worms two pairs of gonads, in segments xi. and xii. respectively. 

 Each gonad is pear-shaped, and attached to the anterior wall of 



