BY G. I. PLAYFAIR. 149 



Fig. 2. — Nodularia spumigena Mertens ; (a) infertile filament with 

 three forms of heterocyst; (b) with ripe spores; (c) with 

 immature spores. 



Fig. 3. — Oscillatoria sjAendida var. attenuata W.& G.S.West. 



Fig. 4. var. limn etica (hemm.) mihi. 



Fig. 5. var. hacilliformis, n.var. 



Fig.G. var. amylacea, n.var. ; (a, h, d) rare 



forms of apex ; (c) filament with sundered trichome, show- 

 ing sheath and also the common type of tip. 



Fig. 7. — Oscill. splendida var. amylacea forma clarescens, n.f . ; the 

 markings hardly visible. 



Fig. 8. ■• incipient filaments, outgrowth 



of motile cells; (a) on Ocdogonium (x330); (b) on vege- 

 table debris; (c) on previously deposited living cells; (d) 

 becoming filamentous by growth. 



Fig. 9. — Oscillatoria tenuis Ag. 



Fig. 10. var. chlorina, n.var. 



Fig. 11.= — Lyngbya Lismorcnsis, n.sp. ; {a, b, c) common and charac- 

 teristic apices; {d, e, /) rare forms of tip; (g) broken fila- 

 ment showing sheath. 



Fig. 12. var. nigra, n.var. ; (a) with broad 



smooth dissepiments and fine incipient septa ; (6) with 

 granulate septa. 



Fig. 13. — Fliofmidiumtcnuc (Menegh.) Gomont; («) three forms of 

 trichome in the same filament; (6) tip of a filament with 

 contiguous cells ; (c) a filament with spores. 



Fig. 14. — Fhohnidium fragile (Menegh.) Gomont; two sizes, cells 

 showing the characteristic appearance of the protoplasm. 



Fig. 15. — SpiiuUna major Kiitz. ; two forms. 



Fig. 16. laxissima G.S.West. 



Fig. 17. Corakiana, n.sp. 



Fig. 18. — Mcrismopcdia punctata var. oblonga, n.var. 



Fig. 19. ■ elegans A.Braun. 



Fig. 20. — Coelosphccrium Kutzingianum Ntig. (x500). 



Fig. 21. — ■ var. punctata (Nag.) mihi; 



(a) diam. 2/x ; (b) 5/x x 2/x ; (c) 5/z x 5/x ; (d) tetraedral 

 form, diam. 6 /x; (tO eight-celled cconobium, diam. 8/x; (/') 

 diam. 10 /x; (g) diam. 12 /x; (h) diam. 16 /x : (a) to (h) show- 

 development of a young form of Codospharium Kutzingi- 

 anum from the single cell. In profusion in No. 16, the 

 above all noted in the same drop. 



