446 J. MCA. KATER. 



EXPLANATION OF PLATES. 



Figures i to 5 and 15, 20, and 21 made from material fixed in corrosive-acetlc- 

 alcohol and stained with iron-alum-hsematoxylin, Figs. 4, 5, and 15 counterstained 

 with light green. The remaining figures from material fixed in Benin's solution 

 and stained as above. All drawings made with Abbe model camera lucida. 

 Magnification 3,200 X. 



PLATE I. 



FIG. i. Small yeast cell showing fine granular lines of chromatic material in 

 the cytoplasm, nucleus partly obscured. 



FIG. 2. Nucleus entirely obscured. Granular lines above vacuole clear. 



FIG. 3. End view of a cell similar to Fig. 2. 



FIG. 4. Cell containing only a few metachromatic granules. Nucleus visible. 

 Medium-sized vacuole. 



FIG. 5. No metachromatic granules. Nucleus very large and structure clear. 



FIG. 6. Nucleus above vacuole which is not so clear as in side view. 



FIG. 7. Cell exhibiting crescentic form. 



FIG. 8. Four connected cells showing manner of connection by unbroken 

 wall. 



FIG. 9. Cross hatching indicates gelatinous secretion which holds the cells 

 together. 



FIG. 10. Resistant cell. Note heavy wall and abundance of metachromatic 

 granules. 



FIG. 11. The same. Metachromatic granules disappeared. 



FIG. 12. Resistant cell showing departure from spherical form and shrinking 

 of protoplast. 



FIG. 13. Resistant cell that has been kept dry for one year. 



Drawings by G. T. Kline. 



