28 F. W. GAMBLE AND J. U. ASH WORTH. 



ture through the body-wall, which thins out at this point 

 (Pis. 1 and 4, figs. 1 and 22, NO.). 



The blood-supply to the nephridia (PL 4, fig. 18) is derived 

 from the ventral segmented vessels, which divide, one branch 

 going to the funnel of the nephridium and the other to the 

 body-wall. The former traverses the funnel, sending a vessel 

 into each of the ciliated processes, and giving ofi* numerous 

 small branches to the lips of the funnel. After traversing the 

 funnel the vessel runs over the secreting portions of the nephri- 

 dium, supplying the genital strand in its course, and finally 

 ramifies on the terminal portion. The blood is collected again 

 into small vessels, which open into the dorsal longitudinal or 

 nephridial longitudinal vessels of the body-wall, from which it 

 is returned largely to the dorsal or subintestinal vessels, but 

 in part passes into the parietal vessels. 



In young specimens the funnels are naturally simpler, but 

 have similar positions and relations, as may be seen in figs. 16 

 — 18, which show nephridia from worms 29*5 and 44 mm. 

 long, in which the processes on the dorsal lip are being formed. 

 In the post-larval stage (Benhara, 1893) the nephridia have no 

 funnels, the development of which has still to be investigated. 



10. Coelora. 



The coelom ofArenicola is well developed, and continuous 

 in all its parts. Not only does it form the space between the 

 alimentary tract and body-wall from one end of the body to 

 the other, but it is carried along with the blood-vessels into 

 the intermuscular spaces. Thus the blood-vessels of the pro- 

 stomium, of the buccal sheath, and of the body-wall generally, 

 are accompanied by coelomic canals which very probably serve 

 as lymphatic spaces from which nutritive matters can be 

 absorbed by the surrounding tissue, and into which waste 

 nitrogenous substances may be excreted. 



The segmentation of the body-cavity is very faintly marked. 

 Anteriorly three diaphragms, perforated just above the nerve- 

 cord, are present, whose position and relations are indicated 



