On the Structure and Affinities of Saccocirrus

Abstract

When studying the morphology of the excretory organs of the Polychæta, I thought it advisable to investigate those few cases of worms in which the true nephridia have been alleged to function as genital ducts. Of these Polychætes, Saccocirrus papillocercus, Bobr., is one of the most interesting ; and whilst occupying for a short time last winter, at the Zoological Station at Naples, a table kindly placed at my disposal by the committee of the British Association, I had an opportunity of studying its structure.