442 EDWIN S. GOODRICH. 



each is a " tube-bearing " flagellated cell, somewhat similar in 

 structure to those I have described in Nephthys (4). Occa- 

 sionally two or even three tubes may open into the same 

 chamber (figs. 12, 14, and 21). 



Each of these peculiar cells consists of a little rounded mass 

 of finely granular colourless protoplasm, in which is placed the 

 round nucleus, supported at the free end of a long conical 

 tube. As in the case of Nephthys, so in Glycera, the nuclei 

 of the tube-bearing cells have the property of staining very 

 deeply and rapidly. The tube itself is formed of a thin layer 

 of cuticular substance ; it is flattened from side to side,^ in- 

 serted by its narrow end into its cell, and by its broad end into 

 the roof of the nephridial chamber. Thin longitudinal lines 

 give it the appearance of being delicately fluted. A long 

 flagellum attached to the cell at the apex of the tube works 

 rapidly within the latter, reaching into the underlying nephri- 

 dial cavity. 



The tube-bearing cells rarely, if ever, stand alone. They are 

 not ranged in rows as in Nephthys, but are dispersed over 

 the whole surface of the nephridium in pairs, or in groups of 

 three, four, or even five cells, resting against each other, no 

 doubt for mutual support. In this position the cells form 

 roundish masses without actually fusing, and project into the 

 coelomic fluid, standing on their tubes as on stilts. The tube 

 is so delicate, and the entire apparatus so slender, that the 

 mere action of the flagellum inside often makes the whole cell 

 waggle backwards and forwards. In a teased preparation of a 

 nephridium the tube-beariug cells may break away from the 

 chambers, and move about in the fluid actuated by the long 

 projecting flagellum : in this condition their resemblance to 

 the collar-cells of sponges is most striking (fig. 5). For these 

 peculiar nephridial cells bearing a tube and a flagellum, which 

 I have hitherto designated by the cumbrous descriptive term 

 " tube-bearing cell," both in the Nephthyidaj and in the Gly- 

 ceridae, I now propose the more convenient term solenocyte 

 awXr'iv, a pipe). As far as I have been able to make out 

 ^ The tube is shown m profile in fig. 14, at the left-hand lower corner. 



