2(j() EXrLANATIOxX OF THE PLATES. 



Fio- 2 A matured froud of Eydrogaslrum granulatum (Linn.), enlargod 90 diameters. 



Fig' 2 a. A resting spore of tlae same, enlarged 160 diameters ; also a minute, very young frond, 

 magnified 90 diameters. 



Fig. 4. A brandi of a Slujeoclonium, emitting zoospores, cnlai-gcd 400 diameters. 



Fig. 5. Bulbolrichia albida, Wood, magnified 460 diameters. 



Fig. 6 a. A fertile branch of Bulbochecle Canbijii, Wood, showing the matured spore, magnified 

 260 diameters. 



Fig. 6 b. A young plant. 



Fig. 6 c. A branch with young male plants, and a forming zoosporangium, magnified 2G0 



diameters. 



Fig. 6 d. The empty cup left after the discharge of the oospore. 



Fig. 6 e. Outline of sporangium. 



Fi"-. 9. A young plant of Stlgeoclonium. 



The globular figures in the lower part of the jilatc are separate cells of Porphrydium magmficum, 

 Wood, magnified 760 diameters. The numbering of the figures at the bottom of the plate are 

 wrong, fig. 3 should read fig. 4, 4, 5, &c. 



PLATE XVII. 



Fi"-. I a. The basal portion of an old frond of Schizomeris Leibleinii, Ktz., ? magnified 120 



diameters. 



Firi-. 1 b. A filament emitting zoospores, magnified 250 diameters. 



Fi"-. I e. A perfected zoospore. 



Fi"-s. 1 d, 1 e, 1 c. Young plants formed by the germination of the zoospore, magnified 450 

 diameters. 



Fig. 2 a. The distal end of a filament of (Edogoiiium Huntii, Wood. 



Fig. 2 b. Cells showing the formation and growth of a new coll. 



Fin-. 2 c. A portion of filament containing spores in dififereut conditions of maturity. 



Fig. 2 d. A young female plant with attached dwarf plant. 



Fig. 2/. Cells emitting a zoospore, magnified 250 diameters. 



Fig. 2 g. The perfected zoospore. 



Fi"-. 2 h. Outline sketch of a young male plant, magnified about 1200 diameters. The arrows 

 are meant to represent cyclotic currents. 



Fi"-. 3. A fertile filament of CEdogonium muUispora, Wood, showing spores in different states of 

 matui-ity, and dwarf male plants. 



Fig. 4 c. Sterile cells of Spirogyra dubia, Ktz., enlarged 260 diameters. 



Figs. 4 and 4 d. Outline sketches of cells containing spores, magnified 260 and 160 respectively. 



Figs. 5 a and 5 6. Sterile cells of Spirogyra rivularis (Hassall), magnified 260 diameters. 

 Fig. 5 c. Outline sketch of conjugating cells with spore similarly amplified 



PLATE XVIII. 



Fig. la. A young female plant of rringsheimia insequale, Wood, magnified 250 diameters. 



Fig. 16. A portion of an adult female plant, containing immature spores, and showing in out- 

 line in the upper sporangium the orifice through which the spermatozoa enter, magnified 250 dia- 

 meters. 



Fig. I c. The supposed young male plant, magnified 450 diameters. 



Fig. 2. (Edugonium inirabile, Wood. A portion of a filament with a partially matured spore. 



