ABSORPTION OF NUTRIMENT BY MUSSELS 417 



some cases these green bodies were almost spherical. This 

 was especially true of the larger granules. In general the diame- 

 ter of the granules varied from less than one micron to that of 

 three or four microns. Green colored granules were also found 

 clinging to the outer ends of the cells or adhering to the cilia. 

 Figure 21 shows the filaments of a mussel kept in the water and 

 Janus green. In this case no green granules were found either 

 within the cells or on their outer surfaces. In some cases, 

 both in the mussels that had been in the solutions and in the 

 controls, the entire cytoplasm of the cells of the outer ends of 

 the filaments showed a pale green tint. The granules in ques- 

 tion, however, took a much deeper stain and were readily dis- 

 tinguishable from the surrounding cytoplasm. 



Similar experiments were carried out in which the mouths 

 of the mussels were closed with paraffin plugs. Exactly the 

 same results were obtained. In figures 22, 23 and 24 are shown 

 gill filaments of a mussel which had been in the stained solution. 

 The black dots represent green granules and spherules which 

 were found within the cells and corpuscles and clinging to the 

 outer ends of the cells. The mussels used as controls in these 

 experiments had no definite green granules within the cells 

 or on the outer ends, though the cytoplasm often exhibited a 

 faint green tint, as did that of those which had been in the stained 

 solutions. A drawing of the gill filaments of one of the control 

 mussels would present the appearance of the filament shown 

 in figure 21. The presence of the green tint found in some cases 

 over the entire cytoplasm does not militate against the efficacy 

 of the Janus green as a specific stain for the albumin, Sudan III, 

 while it is a specific sta'n for fat, often imparts a reddish tint 

 to the entire cytoplasm, but stains the fat droplets a much 

 deeper hue. 



Figures 25, 26 and 27 represent respectively portions of the 

 palp, foot and mantle of a mussel which had been in the stained 

 solution. The mouth of the mussel had been closed with a 

 paraffin plug. Green granules were found in the epithehal 

 cells of all three tissues. 



