730 EDWIN S. GOODRICH. 



provided with a small funnel, evidently a true nephrostome, 

 projecting and opening into the coelom (fig. 49). Its fringed 

 lip, with ciliated protoplasmic processes, bears a remarkable 

 resemblance to that of Nereis (8, and this paper figs. 41, 42, 

 and 44). It seems but reasonable to suppose that this organ 

 can be converted into the wide-mouthed " nephridium " of 

 the adult worm only by the addition of a genital funnel 

 derived from the coelomic epithelium. 



The comparison between the large funnel of the excretory 

 organs of such a worm as Eunice (fig. 21), and the genital 

 funnel of the CapitellidaB, might seem, at first sight, some- 

 what strained and fanciful. But the two structures are so 

 similar in structure and function, and the intermediate steps 

 (Hesionidee, etc.) are so complete, that no other view seems 

 now to be admissible. Although I do not wish to lay too 

 much stress on histological similarity, and such resemblances 

 may perhaps rarely be sure guides to the identification of 

 homologous organs, yet, I think it will be admitted, that the 

 presence of the peculiar and almost identical ciliated ridges 

 on the surface of the large funnels of such widely separated 

 forms as Nephthys, Nereis, Fallacia, Eurythoe,^ and Tere- 

 bella, can scarcely be due to mere coincidence. 



Moreover, it must be remembered that the two organs are 

 mutually exclusive : never do we find a separate genital funnel 

 in those forms which possess wide-mouthed excretory organs ; 

 and conversely, with the one possible exception of Polygor- 

 dius,^ never do we find Polychtetes having nephridia with 

 only small true nephrostomes without genital funnels. 



The fact that no external pore has been found to the 

 supposed genital funnel of the Nereids and Glycera cannot 



" post-larval stage," denying the presence of a nephridial funnel (" The 

 Anatomy and Classification of the Arenicolidae," ' Quart. Journ. Mic. Sci.,' 

 vol. 43, 1900). I can only state that funnels were certainly present in the 

 specimen I examined at Plymouth, and moreover that the ciliated processes 

 have nothing to do with the ciliated folds of the adult organ. 



' An observation I made on a large species dissected fresh. 



' See pp. 715 aud 734. 



