ON THE MORPHOLOGY OF THE NEPHRIDIUM OF NEREIS VEXILLOSA GRUBE

Abstract

1. The morphology of the nephridia of Nereis vexillosa Grube is described. 2. Comparisons are made with the morphology of the nephridia of certain other nereids and differences are noted. Chief among these are, in N. vexillosa: a. that ciliation extends along the whole length of the nephridial canal, with the exception of a short region just preceding the nephridiopore; b. that three general regions of the nephridial canal are noted, on the basis of the diameter and the amount of convolution; c. that the wall of the nephridiopore appears to be inserted on the invaginated surface cuticle. 3. A reconstruction of the nephridial canal is presented in which the course of the canal is readily seen.