710 EDWIN S. GOODEICH. 



Now I shall endeavour to show that the remarkable changes 

 undergone by the excretory organs at the time of maturity in 

 the fertile segments of those Syllids which do not form buds, 

 and in the segments of the reproductive buds, when they 

 occur, described by these and other authors, are really due 

 not so much to the mere enlargement of the true nephridium 

 as to the addition at its anterior end of a new growth, the 

 genital funnel. 



In the immature condition the nephridia of all the Syllids 

 I have examined are of essentially the same structure, 

 differing only in certain unimportant details. In fig. 34 

 is represented the anterior end of the nephridium of Try- 

 panosyllis sp. The lumen of the canal is surrounded by 

 a wall of granular protoplasm containing many excretory 

 granules and vacuoles. Cilia are present here and there in 

 groups attached to the inner surface. In front of the septum 

 the canal projects, and ends by a small funnel, the lower lip 

 of which alone protrudes far into the coelom, and bears a 

 flame-like bunch of cilia. Two nuclei can be detected, even 

 in the living worm, in the lower lip of the nephrostome. The 

 upper lip is not provided with cilia (fig. 34). It is formed of 

 a mass of closely -packed cells continuous with the coelomic 

 epithelium of the septum. These are well seen in a section 

 through the nephrostome of an anterior nephridium of 

 Haplosyllis spongicola (fig. 37). In this species, how- 

 ever, small cilia appear to be present in this region also 

 (fig-. 39). The lower lip of the nephrostome, as is well 

 shown in the latter figure, projects quite freely as a flattened 

 process. 



In Syllis vivipara (fig. 36) the lumen of the nephridial 

 canal is surrounded by vacuoles, some of which at all events 

 open into it. Minute globules are also scattered about the 

 substance of the wall. These globules of varying size, and 

 the large vacuoles, appear to be formed by the accumulation 

 of fluid excretory products absorbed by the nephridial cells, 

 and passing into the lumen of the canal, whence they are 

 driven to the exterior by the cilia placed on its internal wall. 



