EXPLANATIONS AND REFERENCES, 

 PLATE CLV. 



PAGE. 

 Fig. 1-8. FUGLED A VIRIDIS, Ehrb., normal forms, capable of polymorphic 



contours, ..... 161 



" 9-lo. Cells contracting and coming to rest forming encysted spores, . 162 

 " 16-19. Advanced stages of encysted spores dividing into two, and into 



four parts, . . . . . . .162 



" 20. Encysted forms often occurring in countless numbers, . 162 



Figs. 21, 22. iSporangial bodies with escaping microzoogonidia, . 162 



" 23,24. CHLAMYDOMONAS PUJ.YIUSCUL.US, Ehrb.,. . . 168 



Fig. 2o. An encysted form divided into two, . . .168 



Figs. 26, 27. A similar form divided into four parts, . . . 168 



Fig. 28. Cell divided, forming new encysted cells, . . . 168 



" 29. Two red resting cells, ..... 168 



" 30. Macrozoospore ; contents dividing, .... 1'58 



" 31. A cell with contents divided and developing microzoogonidia, 168 

 " 32-35. WOLFFIA COLUMBIANA, Schleiden. 



A plant which has no claim to a place in this volume ; it is ad- 

 mitted as an illustration. It is the smallest of phenoganious 

 plants, and is a form very apt to deceive in the search for fresh- 

 water algae. It is found in wet, marshy, places, not frequent, 

 but in quantity when it does occur. Fronds are rootless, float- 

 ing as small grains, about the size of poppy seed, in shallow, 

 stagnant waters. Cells broadly oval. Multiplication takes place 

 by the formation of a daughter cell in the maternal frond, 

 which opens at one end and the young slides out. Figs. 32-35, 

 represent progressive stages of proliferation. 



" 36-40. MICHOCOCCUS CONFERVICOLA, matured plants and young de- 

 veloping forms, ....... 200 



" 41. COSMOCLADIUM PULCHELLUM, figure transcribed from Raben- 



horst ; hitherto not found in the 

 United States. 



