218 F. KEEP.LE AND F. W. GAMBLE. 



PLATE 13. 



Fig. 1.— Egg-capsule of Coiivoliita filled with a dense mass of flagellated 

 green cells forming a pure culture of the infecting organism, X 35. 



YiG. 2.— Tlie same capsule under slight pressure. Tlie flagellated cells are 

 swarming actively and escaping tlirougli the ruptured wall, 



EiG. 3. — The smaller green cells (microcytes) of the infecting organism in 

 tlie active phase, showing the delicate wall, four flagelhi, chloroplast, stigma 

 and clear "neck" of cytoplasm in which the nucleus is lodged. (For 

 histology see also Fig. 12 b, PI. 14.) 



Fig. 4.— The larger green cells (macrocytes). (No contractile vacuoles in 

 either form of green cell.) Cf. Fig. 12 a. 



Fig. 5. — A portion of the egg-capsule; the green cells have come to rest 

 and lie in pairs. 



Fig. 6.— The infection of an egg-capsule hy the green cells chemotactically 

 attracted thereto (see pp. 188, 189 of text). 



Fig. 7. — Infected capsule, more highly magnified. Green cells (and 

 bacteria) seen on the outer edge of the capsule. Other green cells have made 

 their way through the capsule to the egg {ov.). 



Fig. 8. — Peculiar colonial form of the green-celled infecting organism (for 

 regular palniella stage see Figs. 14 and 15, PI. 14). Non-flagellated green 

 cells in inverted position borne at the ends of branching columns of stratified 

 mucilage. 



Fig. 9. — Dorsal portion of transverse section through the body of an 

 adult Convoluta roscoffensis showing the structure, arrangement, and 

 relations of the green cells. The mnjorlty of the green cells have no nuclei, 

 some mere granular traces. The green cells are arranged in rows running 

 inward from the periphery ; the outermost green cell of a row has a nucleus 

 (red). Indications of continuity between green cells are seen and the close 

 relation between them and the mesenchyme cells of Convoluta is shown. 

 X 750. 



Fig. 10. — Another more highly magnified section through the body of 

 Convoluta (fixed with Fleming, stained with safranin). Four green cells 

 suspended by slender |)rocesses from the basement membrane and separated 

 by mesenehymatous cells. The green cell on the left hand has a nucleus 

 {Nu. gc), the others contain only granules which stain deeply with safranin ; 

 similar deep-staining granules arc also plentiful in the subjacent mcscnchyma 

 (Cam. luc, oc. 12, ol)j. ^.^). 



