Description of Plates 243 



4-6. Stichococcus scopulinus. Showing the variation in the length of the cells, 

 and the coccoid state (53 1 )? P- 161. 



7-9. Stichococcus Jluitans. Filaments breaking up, and the coccoid state (575 ), 



p. 165. 



10-13. Stichococcu rivularis. Terminal and intercalary rhizoidal hooks (568), 



p. 166. 



Plate 23 (575 : 1) 



1. Microspora amoena. (447 A), p. 170. 



2. Microspora crassior. (620), p. 169. 



3. 4. Microspora Loefgrenii. (351, 447 B), p. 171. 



5. Microspora Wittrockii. (348), p. 1 7 2. 



6. A filament from the same material, showing the structure of the cell- wall after 

 prolonged preservation in pyroligneous-acid-formol solution. 



7. One of the H units of the cell- wall. 



Plate 24 (575 : 1) 



1. Microspora floccosa. A filament with greater diameter and more inflated cells 

 than usual (349), p. 174. 



2. A typical filament in active growth, with somewhat reduced chromatophore 

 (409)- 



3. A filament containing zoospores (599). 



4. Akinetes and two dead cells (283 A). 



5. Microspora Willeana. A vegetative filament, with dead cells at top and bot- 

 tom (609), p. 175. 



6. An aplanospore or dead zoospore, a dead cell, and an akinete (609). 



7. End of a filament of akinetes (609). 



8. 9. Microspora tumidula. Vegetative filaments (600, 679), p. 177. 



10. The structure of the cell-walls brought out by prolonged preservation in pyro- 

 ligneous-formol solution (283 C). 



11. Formation of akinetes (573 A). 



12. Microspora stagnorum. Vegetative filament and zoospore formation (495) 

 p. 176. 



13. A vegetative filament with long cells (66). 



14. Microscopa quadrata. End of a filament from material which formed a furry 

 coating on sticks in an aquarium (669), p. 178. 



15. Filament from a confervoid mass (423). 



Plate 25 (575 = 1) 

 I, 2. Tribonema botnbycinum. Varying forms of vegetative cells (430, 421), 

 p. 184. 



3. Cells pulling apart for dispersal of zoospores (128). [This single figure was 

 originally drawn from living material with ocular 3 and objective 7, and later was en- 

 larged to the scale of the rest of the plate.] 



4. Tribonema bombycinum forma tenue. A filament drawn at the time of collec- 

 tion, October 19th (499 A), p. 185. 



5. From the same material, drawn October 30th, showing the change in the chro- 

 matophores produced by better nutritive conditions. 



6. A common form (443 B). 



7. 8. Tribonema minus. (443 C, 428), p. 186. 



