228 Freda Bage : 



segment 20 the nephridia are irregular in shape, and appear to 

 be connected with one another by a loose band of tissue which, 

 in its turn, is connected with the anterior septum of each 

 segment, [Fig. 6.] 



M icrosropir Strurfurt. — A series of sections confirms the 

 general arrangement seen by dissection. Towards the posterior 

 end of tl)(^ body, the tiepliridia, into which the funnels open, are 

 connected with one another by means of the loose connective 

 tissue noted above. Through this ramify many ducts [Fig. 7], 

 which soon pass off singly through the longitudinal muscles 

 to what seems to be a sinus between the two layers of nmscles. 

 From this sinus branched ducts lead again to the exterior. I 

 was unable to trace any one duct right through to the external 

 opening, as they form such a confused network. Further, from 

 my sections I could not decide whether or not there was a con- 

 nection of the ducts from segment to segment, but apparently 

 the sinus was continuous through all the segments examined. 

 At the very anterior end there is a mass of nephridial tubules, 

 one on either side of the pharynx, which were recognised by 

 Professor Spencer as doubtfully peptonephridia. I have not 

 been able to find any ducts opening from these to the alimen- 

 tary canal, and Miss Raft", who is working on the structures 

 connected with the alimentary canal, has not only failed to 

 discover any connection a\ ith the pharynx, but has traced ducts 

 from the tufts which open to the exterior, so that they must be 

 regarded as a tuft of micronephridia. and not as pejUo- 

 nephridia. 



3. - Dipopochaeta davallia, Spencer (17), p. 52. 



The nephridiopores could not ])e distinguished with the 

 naked eye, })ut on dissection tlie ducts from the nephridia to 

 the exterior are seen to open at the level of tlie interval 

 l)etween the fourth and fifth setae from the ventral surface; 

 that is, about halfway between the mid-ventral and mid-dorsal 

 lines. (See also Spencer (G), p. 52.) 



The nephridial system ie meganephric. 



Macrosarpic Structure. — Tliere are, except in the Hrst and 

 second segments, one pair of meganephridia in each segment. 



