PHYLUM ANNELIDA 



207 



nitrogenous wastes from the coelom into the tubule where it can pass 

 to the outside through the nephridiopore. Also the wastes in the 

 blood are excreted by way of the nephridial tubules. The nephro- 

 stome is located in the posterior part of the segment and leads into 

 the tubule of the segment just posterior to it. The nephridium coils 

 two or three times before reaching the nephridiopore. 



Tl^t 



^...^.'S-. 107.— structure of a nephridium from earthworm, a, ampulla between the 

 ciliated and nonciliated portions of the intracellular canal ; 6il, ciliated canal coe 

 nn^Mr'^f'^^^'^ ^''T' coelomic epithelium; ext, external opening ^nephridiopore) Zc^ 

 fneT ?;/**in^ter.^iii T^'' septum between somites; nst, nephrostonie^ (internal open- 

 mjWikherf h^ r^^t'^^^"" ^anal. (From Parker and Haswell : Textbook of Zoology, 

 published by The MacmiUan Company, after Meisenheinmer, after MazE^irski.) 



