700 EDWIN S. GOODRICH. 



Already Heriug, Claparede, and Greeff have described in 

 considerable detail the excretory and genital organs of the 

 Alciopinee, and Gravier those of the Phyllodociuae ; but since 

 these authors failed to recognise the essential structure of 

 the true uephridium, and its distinctness from the genital 

 funnel with which it becomes connected at maturity, it will 

 be more convenient to delay the consideration of their writ- 

 ings until after I have dealt with my own observations. 



Alciopinae. 



The Nephridium. — On examining with the microscope a 

 living specimen of Vanadis formosa compressed under a 

 cover-glass, the nephridium can be seen in every trunk seg- 

 ment, after the first two or three, as a long slender tube 

 running ventrally along the side of the body, between every 

 consecutive pair of parapodia (fig. 1). Each nephridium 

 opens ventrally, and just in front of the base of a para- 

 podium. The external opening leads into a slightly dilated 

 chamber, which is continued into the nephridial duct extend- 

 ing forwards, and ending blindly in the posterior region of 

 the next segment ; for the very incomplete septum here 

 allows the elegantly curved nephridium to project beyond it. 

 Bunches of solenocytes are set at irregular intervals along 

 the nephridial canal, chiefly on the outer edge of the curved 

 surface (fig. 1). 



The nephridium of Alciope cantrainii is very similar to 

 that of Vanadis ; but the canal branches anteriorly, and the 

 solenocytes are fewer in number, and grouped near the ex- 

 tremities of the blind branches (fig. 3). The bladder-like 

 dilatation near the external pore is more marked (fig. 5). 



In Aster ope Candida the nephridium is more like that 

 of Vanadis that that of Alciope. 



The detailed structure of the solenocytes in the Alciopinae 

 and their relation to the nephridial tube are of considerable 

 interest. The tubes themselves are of remarkable length, 

 especially in Alciope (fig. 3), nari'ow, of almost even dia- 

 meter throughout, and slightly oval in section. They pierce 



