MALAY FORM OF CHLOROCOCCUM HUMICOLA. 481 
EXPLANATION OF TIIE PLATES. 
PLATE 17, 
Figs. 1-10 and 13 x 825, figs. 11, 12, and 14 x 1435. 
1. Small vegetative cell with an irregular parietal chloroplast and one pyrenoid. 
2, Cell with chloroplast having a single small perforation and six pyrenoids. 
3. Cell with small thickenings on the cel'-wall. 
4. Two daughter-cells still united by a gelatinous investment produced from the 
disintegrated mother-cell-wall. 
5. Small cluster of cells showing the formation of two daughter-cells within the 
mother-cell-wall. 
Figs. 6-9. Multiplication by zoogonidia in cells of varying sizes. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
iz] 
10. Empty zoogonidangium with small internal thickenings of the cell-wall. 
11. Zoogonidia of different forms. py., pyrenoid ; pig., pigment-spot. 
12. a-e, Successive stages in the conjugation of isogametes; d, zygote with thin 
cell-wall before the loss of cilia. 
13. Young vegetative cells developing from zoogonidia or zygotes. 
14. a-e, Unusual conditions in conjugation. «, Formation of zygote with two cilia at 
each end; 5, fusion of anisogametes; c, fusion of zoogonidium to posterior end 
of young zygote; d, abnormal zoogonidium set free before division is complete; 
ch, chloroplast. 
PLATE 18. 
Figs, 15-24. Sections to show cytological characters, x 1435. 
. 15. Small cell stained with Heidenhain’s hematoxylin showing reticulate cytoplasm, 
a single nucleus (v.), and one pyrenoid (py-). 
.16. Do. showing two nuclei, a pyrenoid dividing by constriction, and a parietal 
. 
chloroplast. 
. 17. Do. showing finely reticulate cytoplasm, with two nuclei and one pyrenoid. 
a and b, two drawings of the same cell at different levels. 
ig. 18. Larger cell showing more numerous nuclei and pyrenoids, and indications of a 
parietal chloroplast. 
. 19. Do. with very numerous nuclei and a number of large pyrenoids; the cytoplasm is 
more distinctly reticulate than in the smaller cells. 
. 90. Pyrenoids of various forms. 
.91. Cell just before the formation of aplanospores, showing enlarged nuclei with 
variously shaped karyosomes, c-n., nucleus dividing by constriction. 
g. 22. Section through mass of young aplanospores. m., mucous investment formed by 
the disintegration of the mother-cell-wall ; n., nucleus; py., pyrenoid. 
23. Sections of cells in palmelloid condition. a-c, Stained with Heidenhain’s 
hemtoxylin; d, stained with Delafield’s hamatoxylin, showing the reticulation 
of the cytoplasm ; m., mucilaginous investment; n., nucleus; py., pyrenoid. 
. 24. Section of cells as in fig. 5, with pyrenoids showing distinct plates in the starch- 
sheath, an enlarged nucleus, and indications of a parietal chloroplast. 
Figs. 25-81, Multiplication by means of aplanospores. X 825. 
bo 
c 
. Group of mother-cells filled with young aplanospores which are angular by 
compression, : 
i 
ANS. ee O, 
