484 FRANK E. BEDDARD. 



the network of Megascolides, but in quite a diagrammatic 

 way. I think, however, that the figure which I now give (fig. 

 7) of the network in Acanthodrilus is sufficient to con- 

 vince anyone of the reality of its existence. Usually the net- 

 work exhibited the characters shown in that figure ; that is to 

 say, the individuality of the several tubes was quite distinct in 

 spite of their anastomoses in every direction and at such fre- 

 quent intervals. Very often, however, the network exhibited 

 the appearance shown in fig. 2 ; here it will be observed that 

 the tubes are in very close approximation, so much so that the 

 mass formed by their fusion presents the appearance 

 of an irregular system of lacunse enclosed within a 

 definite wall. This character, it is perhaps worth remark- 

 ing, belongs to the nephridia of several invertebrate groups. 



In describing the nephridia of Acanthodrilus I stated 

 that the tufts of successive segments were isolated from one 

 another ; this is, however, as shown in fig. 9, not always the 

 case. In that figure, which represents a longitudinal section, it 

 will be seen that the nephridia which pass up the septa do not 

 always open at once into the lumen of the gut, but apparently 

 become connected with nephridial tubes derived from other 

 segments, and course along the walls of the gut; a communi- 

 cation is thus established between the nephridial 

 networks of a number of segments. In fig. 8 is illus- 

 trated a portion of one of the septa which is invaded by the 

 nephridial tubes on their way to the intestinal walls : it will 

 be seen that in such places hardly any traces are left of the 

 muscles of the septum ; the septum appears to be entirely 

 built up of a mass of frequently anastomosing nephridial 

 tubes. 



I have not yet examined a large series of earthworms with 

 diff'use nephridia, with a view of finding out whether anal 

 nephridia are present in other species. I believe, however, 

 that they are not present in A. antarcticus — a near relative 

 of A. multiporus. 



It is of importance to find undoubted nephridia in a com- 

 paratively low type of Chfetopod opening into the anal section 



