226 Freda Bage : 



a curious additional pair of lueganepliridia present on the dorsal 

 surface of the more posterior segments of the body. Each of 

 these dorsal nephridia also has a well-developed funnel. The 

 arrangement of the meganephridia Avas examined in one speci- 

 men which consists of 120 segments. [Fig, 1.] The micro- 

 nephridia were present in every segment, ventral meganephridia 

 in segments 21 to 120, while the dorsal meganephridia were 

 present only in segments 50 to the posterior end. The parts of 

 the nephridia were too small to be made out by dissection, but 

 a fine thread could be seen connecting the two meganephridia. 

 [Fig. 4.] 



Microscopic Structure. — -By means of series of sections the 

 structure of the meganephridia was made out in part. Both 

 dorsal and ventral tubules appear to be similar in structure, 

 and to consist of the same series of parts. Tlie structure of 

 the funnel is different from that of any other species exam- 

 ined, the cells composing it being very few in number, appa- 

 rently only five, and extremely large in size. [Fig. 2, c] 

 These are, as usual, ciliated, and the nuclei are distinctly seen 

 in stained sections. The cells have their long axes parallel 

 with the length of the body, and are somewhat irregular in 

 shai)e ; thus there is no arrangement to be compared with that 

 of the regular marginal cells of other species. The funnel 

 leads into an intracellular duct {Fig. 2, d.i.], the tubule con- 

 taining which, after passing through the septum to the next 

 posterior segment, divides into two portions [Fig. 3], each of 

 which contains a mass of coiled intercellular ducts. A very 

 fine intracellular duct joining the dorsal and ventral nephridia 

 passes round the alimentary canal attached to the face of the 

 anterior septum by a fine mesentery. The ventral nephridium 

 apparently opens to the exterior by a fine duct which passes 

 out through the muscles. Xo trace, however, could be found of 

 any duct opening directly from the dorsal nephridium. This 

 seems to point to the prol)ability that the dorsal nephridium 

 is simply a portion of the ventral one, which has. together 

 with the spermathecae, come in this form to lie dorsally, and 

 lias ac(|uired a secondary opening into the body cavity. 



The uiicronephridia. although extremely minute, are very 

 numerous, and are attached to the body wall of every segment 



