188 
EDWIN S. GOODlilCH. 
In other regions of the canal they may be more sparsely 
distributed. Cell outlines are rarely visible. The cytoplasm 
Diat^nun of a, section tlirough the nepliridimn, passing along a 
plane at right angles to the long axis of the animal, and 
parallel to the gill bar. 
a. e. Atrial epithelium, h. Base of secondary gill-bar. hv. 
Blood-vessel, c. ep. Coelomic epithelium, cli. Chamber con- 
taining solenocytes. v. Wall of nephridial canal, op. Ne- 
phridiopore. koI. Solenocyte cell, and t. its tube containing 
a flagellum. 
usually contains numerous granules of an excretory nature. 
As we approach the tip of a diverticulum, we find that the 
