THE GREEN CELLS OF CO^VOLUTA EOSCOFFENSIS. 219 



PLATE 14. 



Fig. 11. — Life-liistory of tlie green-celled infecting organism in the free 

 slate. A, Encysted colourless macrocjtes, resting and dividing into colourless 

 daugliter-cells. B, Microcyte dividing. c, Encysted green macrocytes, 

 resting and dividing into green daughter-cells. P, Apparent fusion of two 

 macrocytes (see text, p. 190). n, Apparent fusion of two unequal colourless 

 cells. 



Fig. 12. — a, A typical free macrocyte. B, A typical free microcyte. The 

 nucleus is homogeneous, and in a sends processes towards the bases of the 

 flagella and also towards the pyrenoid. The reticulate surface-cytoplasm is 

 shown, the more internal chloroplast being drawn in optical section. 



Fig. 13. — Green cells from the body of just-infected larval Convolutas. 

 The large nucleus of the recently ingested green cell contrasts markedly with 

 the degenerate nucleus of the daughter green cell budded off later from such 

 a mother-cell. (Cam. luc, oc. 12, ohj. -jL Zeiss.) 



Figs. 14 and 15. — The infecting organism in the ))almella (colonial) stage. 

 A, u show green cells of the palmella organising active cells, c, The empty 

 cyst left after the escape of a flagellated cell. Fig. 15 illustrates the origin 

 of new cells of the palmella by budding. 



Fig. IC. — A, B, c, the gradual disappearance of one of a pair of apposed 

 resting-cells (see text, p. 1S4). d, e, Colourless and green resting-cells. 

 r, G, Formation of colourless daughter-cells within a colourless mother-cell 

 H, Y, Formation and discharge of green daughter-cells. 



