THE NEPHBIDIA OF THE POLTOH^TA. 713 



sion that, owing perhaps to the scarcity of the material at his 

 disposal, he has been entirely misled by appearances. Prof. 

 Mcintosh, whose account resembles somewhat Ehlers' de- 

 scription, does not seem to have been more fortunate. 



The nephridia of the Amphinomidas, as, indeed, we should 

 expect from the general appearance and structure of these 

 worms, resemble in all essential respects those of the Poly- 

 noinae and their allies. They are, in fact, of the ordinary 

 large-funnelled type, formed most probably by the fusion of 

 the genital funnel with the nephridial duct. 



In Euphrosyne the nephridia are paired organs, each 

 opening ventrally by a minute pore, just on the hinder edge 

 of the groove between the bases of two adjacent parapodia, at 

 a point marked * in fig. 40. The nephridial canal is some- 

 what large, slightly coiled, dii-ected from the pore upwards 

 through the body-wall, then forwards to the region of the 

 septum, where a largo number of muscles intersect the ccelom. 

 Coiling round some oblique muscles, it narrows, then opens 

 into a large trumpet-shaped funnel. The only peculiarity 

 about the nephridium of Euphrosyne is that this large funnel 

 opeus backwards into the same segment that holds the 

 nephridial canal to which it belongs. Since the same thing 

 occurs in Eurythoe, it may be concluded that this position of 

 the funnel is characteristic of the family. Such a back- 

 wardly directed opening of the genital funnel is not entirely 

 unprecedented amongst the Polycha^ta, since it has been 

 described by Claparede in Eunice schizobranchia. 



There is in the Amphinomids that marked histological 

 diiference between the structure of the walls of the nephridial 

 canal and of the large ca3lomic funnel which we have found 

 in other cases. Here also, no doubt, the compound organ 

 fulfils the functions both of a kidney and of a genital duct. 



Further Observations on the Hesionidte. 



In Part I (11) I gave a description of the nephridium and 

 genital funnel (ciliated organ) of Tyrrhena and Hesione 

 (Pallacia). The structure of these organs in some other 



