452 EDWIN S. GOODlilCn. 



tions througli the organ, where cells and nuclei can be found in 

 every stage of dissolution (figs. 26 and 25). 



It would appear, then, that the ciliated organ and nephridial 

 sac are concerned in the gathering up, through the agency of 

 phagocytes, of the solid waste products found in the ccelora, 

 whilst the function of the nephridium is to eliminate the 

 soluble excretory material derived from the coelomic fluid, and 

 also perhaps from the sac. The function of the solenocytes 

 or tube-bearing cells themselves is possibly analogous to that 

 of the Malpighian capsules in the Vertebrate, namely, to 

 excrete liquid, which presumably can pass by osmosis through 

 the thin wall of the tube. 



GONIADA. 



The Nephridium. — As in Nephthys and Glycera, so also 

 in Goniada, the nephridium is au organ without opening into 

 the coelom, and with a branching termination provided with 

 tube-bearing flagellated cells. The organ can best be studied 

 in the large species G. emerita. It consists of a ciliated 

 canal leading to the exterior, which, except near the internal 

 end, is much wider than in Glycera. This canal passes 

 through the septum and emerges on the anterior face, where 

 it branches to form a lohed terminal organ almost exactly 

 intermediate in structure between that of Nephthys and that 

 of Glycera. For whereas in the latter this region spreads out 

 to form a plate, the surface of which is evenly covered with 

 nephridial chambers and scattered solenocytes, and in the 

 former it divides into long branches with a regular row of 

 solenocytes on either side facing each other, in Goniada 

 emerita the terminal organ consists of massive short branches 

 or lobes, on which the solenocytes are set in somewhat regular 

 rows, generally, but perhaps not invariably, facing each other 

 (figs. 33 and 35). These cells are also themselves of inter- 

 mediate character : as in Nephthys, they are fixed at the base, 

 have oval nuclei, long necks, and long tubes ; but the tubes 

 and necks are relatively short, resembling those described 

 above in Glycera unicornis. 



