PLATE 8.— Confervoideae. 



Figure 



1. Aphanizomenon Jlos-aqute, Morr. a, ordinary filaments ; b, filaments with 



spermatic cells ; c, filament with a vesicular cell (heterocyst). 



2. Trichormus muscicola, n. sp. a, filament with vesicular cell ; b, ditto with 



adjoiniug spermatic cells ; c and d, fragments treated with acid to render the 

 membrane and contents distinct ; e and /, spermatic cells similarly treated. 



3. Spjhcerozyya elastlca, Ag. 



4. Cylindrospermum catenatum, Ralfs. 



5. Spermosira litorea, Harv. 



6. Dotichospermum Ralfsii, Thwaites. 



7. Nostoc commune, Yauch. a, ordinary filaments ; b, a single filament in its 



gelatinous sheath ; c and d, fragments with a vesicular cell. 



8. Oscillatoria autumnalis, Ag. a, fragments escaped from a sheath, b. 



9. Microcolens repens, Harv. ; b, fragments showing the single sheaths ; c, d, frag- 



ments treated with sulphuric acid and iodine. 



10. Lynybya muralis, Ag. 



11. Dasyyloea amorplia, Berk. 



12. SirosipTion ocellata, Berk. 



13. Sclrizosiplion Warrenice, Caspary. a, tuft of filaments ; b, c, fragments ; d, e, 



decomposing sheaths. 



14. Tolypottirix distorta, Kiitz. 



15. Ainactis calcarea, Kiitz. ; b, fragment showing the spiral sheath. 



16. Euactis atra, Kiitz. 



17. Schizoihrix Creswellii, Harv. 



18. Rivularia Boryana, Kiitz. 



19. Scytonema Myoelirous, Ag. 



20. Arthronema cirrhosum, Hass. 



21. Petdlonema alatum, Berk. (Artlirosiphon Grtvillii, Kiitz.). a, end of a filament ; 



b, cross section. 



22. Culothrix mirabilis, Ag., a ; b, junction of filaments. 



