PLATE 2 



EXPLANATION OP FIGURES 



13 Gill filaments of Q. ebenus which had been in filtered water for 58 days. 



14 Gill filaments of Q. ebenus which had been in albumin solution for fifty- 

 eight daj's. The relative depths of stippling in this figure and the preceding 

 one have the same significance as in figures 11 and 12. 



15 and 16 Gill filaments of Q. ebenus showing corpuscles entirely surrounded 

 by epithelial cells. D, corpuscles. 



17 and 18 Gill filaments of Q. ebenus which had been in albumin solution 

 with mouth plugged for five days. The heavy dots represent the granules found 

 in the cytoplasm and adhering to the outer ends of the cells. Apochromatic 

 homoegeneous immersion objective and compensating ocular. 



19 Gill filament of Q. ebenus used as control for those shown in figures 17 and 

 18. Magnification as in figures 17 and 18. 



20 Gill filaments of Q. ebenus which had been for eight days in albumin solu- 

 tion stained with Janus green. B, green granules of albumin; C, corpuscles con- 

 taining green granules. 



21 Gill filament of Q. ebenus which had been in water and Janus. green for 

 eight days. Control for figure 20. 



22, 23 and 24 Gill filaments of Q. ebenus which had been with mouth plugged 

 for eight days in albumin solution stained with Janus green. E, green granules. 



25 Epithelial cells of palp of mussel shown in figures 22 to 24. 



26 Epithelial cells of foot of mussel shown in figures 22 to 24. 



27 Epithelial cells of mantle of mussel shown in figures 22 to 24. The black 

 dots in figures 25 to 27 represent green granules of albumin. 



428 



