36 



OLIGOCHAETA 



the external pore, which may be termed the preseptal portion ; the other the much 

 more extensive postseptal portion. 



The preseptal portion consists" of the funnel and of a short tube passing through 

 the septum. The funnel is made up of a considerable number of tall columnar cells, 

 which are ciliated over their entire inner surface ; the connexion of the funnel with 

 the tube is effected in the following way : the tube has the usual intracellular 



Fig- 7- 



NEPHBIDIUM OF LUMBEICUS ILLUSTRATING VASCULAR SUPPLY. 

 (From Beuham.) 



E. F. G. ist, 2nd, and 3rd loops of nephridium. N. Nerve cord. S. Septum. SN. Subnerval bloodvessel. 

 v. Ventral bloodvessel, a. 6. c. Branches of the same. d. Commissure uniting dorsal and subnervian 

 vessels, e. f. Its branches, g. Dilatations on capillaries. 



lumen ; the two sides of this (in optical section) diverge at about the centre of the 

 funnel, ' each bending outwards, and then sharply backwards nearly parellel to its 

 former course.' The lumen ceases at the point of divergence, the cells being only 

 grooved; the cells are continuous with the marginal cells already referred to. The 

 centre of the horseshoe-shaped funnel has now to be accounted for ; this has been 



