274 ANDREWS. [Vol. V. 



Such of the refracting cells as have oblique, clear bases are 

 now seen to have also a vase-shaped inclusion asymmetrically 

 encased in the peripheral base of the cell, as shown in Fig. 5. 



The peripheral portion of one of these refracting cells may be 

 readily separated from the rest, and then, by pressure, the con- 

 tained vase-shaped inclusion forced out of it. In this process 

 a circular, cup-shaped, slightly granular disk, with a central 

 hole or depression, is pulled off from the neck and shoulders 

 of the vase, leaving it naked and clear. This cup is especially 

 well seen after gold chloride staining, its central opening or 

 deep depression corresponding to the small, cylindrical neck or 

 process of the vase. In this way we remove the softer base 

 of the cell from the more resisting, highly refracting inclusion, 

 the above vase-shaped body. 



When strong potash is used after the last-mentioned macera- 

 tion, the broken-off basal ends of the cells appear very plainly as 

 vase-shaped bodies (Fig. 6) enclosed in faintly granular material, 

 the cell body, especially noticeable at the peripheral end of the 

 cell, as a circular region of the cell representing the above- 

 described broken-off disk. The action of potash upon the axial 

 part peripheral to the nucleus of the cell is to produce rows of 

 drop-like areas, evidently artificial products. 



Using the same maceration, but applying strong nitric acid, 

 the vase-shaped bodies turn bright yellow and become swollen 

 out of shape, the color turning brighter upon the addition of 

 ammonia ; this same reaction is seen in the case of the " carti- 

 lage cells " of the branchiae, which turn more intensely yellow 

 on the addition of ammonia. 



When the isolated basal ends of the cells are treated with 

 hydrochloric acid, the pigment becomes diffused through the 

 vase, giving it a dark red-brown color, with certain oil-like drops 

 or granules in its centre, though the general shape and consist- 

 ency are retained. 



The result of this examination by maceration, as regards the 

 structure of any one of the refracting cells, may be expressed 

 by the accompanying diagram (Fig. 1 in text). The axial part 

 differs from the vase-like inclusion in being less refracting, 

 much less resisting and definite in outline, as if merely clear 

 protoplasm with less clear interpolations. 



The pigment of this cell is confined to a thin, ensheathing 



