[Comparative ultrastructural study of the protonephridium of Eteone longa and the metanephridium of Lumbricus terrestris].

In the initial part of the protonephridium of E. longa specialized cells, cyrtocytes, are observed in addition to cells of the protonephridial duct among which dark and light cells are distinguished. The metanephridial duct of L. terrestirs is characterised by a comples differentiation and subdivision into several parts whose cells deffer in their morphology. The functional role of the two excretory organs is discussed.