110 P. W. GAMBLE, M.SC, AND J. H. ASHWOKTH, B SO. 



rarely both the first nephridia are mere funnels, and agSin one may 

 be fully developed and the other rudimentary, but they are never 

 absolutely wanting. Their small funnels, which are of a bright pink 

 colour, are placed on the anterior face of the third diaphragm with the 

 long axes vertical (PI. VII., Figs. 13 and 14). One lip (the outer) is 

 produced into processes corresponding to the dorsal lip of the other 

 nephridia. The secretory portion is elongated, narrow, and usually 

 brownish in colour, and the terminal portion opens just above the 

 fourth neuropodium (PL VI., Fig. I) at a decidedly lower level than is 

 the case in the succeeding nephridiopores. 



The remaining five pairs are always in adults fully developed. They 

 are attached to the body-wall partly by connective tissue, partly by 

 the broad bands of oblique muscle which obscure them at first sight 

 (PL VII., Fig. 5). The nephrostomes are very long, and bent upon the 

 rest of the organ. The narrow slit-like aperture has a dorsal vascular 

 lip bearing finger-shaped or spatulate ciliated processes, and an entire 

 ventral one. The cilia just within the mouth of the funnel are exceed- 

 ingly long, and produce a current tending to carry ccelomic fluid and 

 corpuscles into the cavity of the organ. The middle or secreting por- 

 tion is brownish (in old worms almost black), owing to the excretory 

 granules which are formed in its cells. The tertuinal rosette-shaped 

 bladder, which is slightly lighter in colour, opens by a minute slit-like 

 aperture through the body-wall, which thins out at this point 

 (Pis. VI. and IX., Figs 1 and 22, NO.). 



The blood-supply to the nephridia (PL IX , Fig. 18) is derived from 

 the ventral segmented vessels, which divide, one branch going to the 

 funnel of the nephridium and the other to the body- wall. The former 

 traverses the funnel, sending a vessel into each of the ciliated processes, 

 and giving off" numerous small branches to the lips of the funnel. 

 After traversing the funnel the vessel runs over the secreting portions 

 of the nephridium, supplying the genital strand in its course, and 

 finally ramifies on the terminal portion. The blood' is collected again 

 into small vessels, which open into the dorsal longitudinal or nephridial 

 longitudinal vessels of the body-wall, from which it is returned largely 

 to the dorsal or subintestinal vessels, but in part passes into the 

 parietal vessels. (See note, p. 118.) 



In young specimens the funnels are naturally simpler, but have 

 similar positions and relations, as may be seen in Figs. 16 — 18, which 



