Studies on Cyanophyceae. 227 
divided. The cells of the lower portion of the filament are still in the 
vegetative condition. 
Fig. 2. A chain of germinating spores, the membranes of the median ones 
have become mucilaginous and are partly confluent. 
Fig. 3. Lateral liberation of the contents of the spore by detachment of a 
lateral piece of spore-membrane which had become lost in the sur¬ 
rounding water ; the stratified mucilage, which causes the liberation of 
the contents, is well seen. 
Fig. 3a. The same process, but in this case the liberated contents have 
already undergone sub-division ; they are surrounded by a well-marked 
mucilage-envelope. 
Fig. 4. The second type of germination ; the spore-membrane has swollen up 
and the contents lie in the resulting mucilage. 
Fig. 5. Part of the spore-membrane only has become mucilaginous; the 
young filament is 3-celled, the cell at one end being a heterocyst. 
Fig. 6. Here only the central part of the spore-membrane has become 
mucilaginous ; the contents of the spore have undergone sub division. 
Fig. 7. Filament with germinating spores, two of which have opened by the 
detachment of a terminal piece of the membrane (lost in the surrounding 
water) and have each given rise to a 6-celled filament, whose base is 
still enclosed in the cup-shaped remnant of the spore-merpbrane; one 
of the lower spores is germinating according to the second type. 
Fig. 8. Compare description of Fig. 5. 
Fig. 9. A germinated spore, whose membrane has become mucilaginous, and 
encloses a young 4-celled filament. 
Fig. 10. Portion of a filament, illustrating a number of variations of the first 
type of germination ; a and b exhibit stages in the ordinary protrusion 
of the contents ; t shows the liberation of the contents by the detach¬ 
ment of a terminal piece of the spore-membrane, which is turned on 
one side like a lid ; l shows a similar case, but here the lid is lateral. 
Fig. 11. Germination of a chain of spores according to the second type ; the 
mucilage round the dividing contents is partly confluent. 
Fig. 12. Compare description of Fig. 9. 
Fig. 13. Various stages of germination according to the second type. In the 
lower spores the mucilage round the contents of several spores is 
confluent. 
Fig. 14. Compare description of Fig. 4. 
Fig. 15. Germination of a spore according to the first type ; the spore mem¬ 
brane has been forced widely open by the mucilage, which now envelopes 
the sub divided contents. 
Fig. 16. cf. description in text, p. 220, footnote 1. 
Fig. 17. Irregular mass of cells, produced by the germination of transversely 
or obliquely elongated spores (cf. text, p. 222). 
Fig. 18. Illustrates the same as Fig. 17 in a somewhat earlier stage. 
Fig. 19. A row of four spores, which are elongated in the transverse direction. 
Fig. 20. Liberation of the spore-contents according to the first type of 
germination ; the aperture, through which they are protruded, is so 
narrow, that they are distinctly compressed at that point. 
Fig. 21. Three spores in the mature condition ; the upper one exhibits a 
slight contraction of the contents previous to their liberation ; the lower 
one has already partly liberated its protoplast laterally. 
Fig. 22. Commencement of the protrusion of the contents in the first type of 
spore-germination ; a small papilla is visible at one end. 
