454 Acton. — Observations on the Cytology of the Chroococcaceae. 
Fig. ii. Dividing cells, showing large metachromatin granules and distinct network. 
Fig. 12. Gomphosphaeria lacustris, stained with iodine-green- fuchsin after formalin. 
Fig. 13. Gloeocapsa sp., stained with iodine-green-fuchsin after Flemming’s solution. The 
apparent thickening of the network in the central region is probably only an artifact due to slight 
contraction. 
Fig. 14 .%Aphanothece prasina\ A, stained living with methylene blue, showing metachromatin 
granules and network in central region, cyanophycin granules in peripheral region ; B and C, stained 
with iodine-green-fuchsin after fixing with chrom- acetic. 
PLATE XXXIV. 
Fig. 15. x 2,500. Chroococcus macrococcus. Section through protoplast, not cutting the nucleus. 
v, vacuole ; m, metachromatin granules ; n, 1 nucleus ’. Stained iodine-green-fuchsin after fixation 
in weak chrom-acetic. 
Figs. 16 and 17. x 2,500. Sections through ‘nuclei’ stained with Delafield’s haematoxylin. 
The interior of the nucleus is seen to be unstained and free from granules. 
Fig. 18. x 2,500. Nucleus stained with Delafield’s haematoxylin, showing division by con- 
striction. The nuclear reticulum is still quite distinct. 
Fig. 19. x 1,450. Cells showing nuclei dividing previous to constriction of cell-wall. Stained 
with Delafield’s haematoxylin after absolute alcohol. 
Figs. 20 and 21. x 540. Illustrating the splitting away of the outer envelope of the cell in the 
normal condition. 
Fig. 22. x 540. From a three-weeks-old culture on damp earth. The cell-wall shows a one- 
sided development. 
Fig. 23. x 540. From an eighteen-months-old culture on agar after three weeks in a 2^ per cent. 
KN 0 3 solution. A distinctly corrugated stalk is formed. 
