BY G. I. PLAYFAIR. 551 



Plate Ivi. 



Fig.l. — Fedi. tefrasvar. lomju-tirnutum (Rac.)(x 13o0). 



l<'ig.2. VAY. austiale, n.var. (xloOO). 



li'ig.3. var. tetraije.dia (Kirchn.) (xloOO). 



Fig.3o. ' var. quadratum, n.var. (xlSOO). 



Fig. 4. var. unicellular e, n.var. (xloOO), (a) side. 



Fig. 5. var. trtaiigulare (Cliodat) (xloUU). 



Fig. 6. var. Crux Michaeli (Rein.) (x 7UU). 



Fig. 7. ■ var. inteyrum (Nag.) f . (x7()0). 



Fig. 8. — Scene, obliquus var. acuminatus (Lag.) Chod.(xo28). 



Fig. 9. — ■■ var. inermis, n.var. (x528). 



Fig. 10. — Tetra'edron lobulatum var. decussatum (Rein.) f. (x700). 



Fig. 11. var. triangukire, n.var. (x700). 



Fig. 12. — Chcetosphcvridium globosum var. 'microscopicunv, n.var. 

 (x350). 



Fig. 13. — Scyt. viirabile (Dillw.) Bornet; (a) narrow, crowded cells 

 resulting from mitosis, (b) cells developing freely, (c) var. 

 ampluni (West), ((/) var. ambiuuum. (Kiitz.), ('') lieterocyst 

 of the type-form; (c) and {d) are the result of a current 

 of water drawing the cells out — the heterocysts are simi- 

 larly lengthened. These three types were all found suc- 

 ceeding one another in the same filament within Jmm. 

 (x350). 



Figs. 14-16. — Calothrix confervicola (Roth.) Ag. (x350). 



Figs. 17-18.. — Oscillatoria nigroviridis Thw. var. australis, n.var. 

 (x350). 



Fig. 19. — Stenopterobia anceps (Lewis) Breb. (x350). 



Fig. 20. var. intermedia (Lewis) ( x 350) ; (a) 



apex in side-view (x700). 



Fig. 21. > var. Heribaudii mihi, slender form, 



no puncta (x3o0). 



Fig. 22. robust form ; (a) with 



marginal dots, (b) with arches (x700). 



Fig. 23. ■ var. detrita, n.var. (x700). 



Fig. 24. — Cycl. Meneghiniana var. mimdissima, n.var. (xlOOQ); 

 (a) side. 



Fig. 25. ■ '— var. major, n.var. (x528) ; (a) side. 



Fig.26.— ^ var. stelligera Cleve et Grun. (x700). 



Fig. 27. ■ var. Kiifzingiann (Thw.) (x700). 



Fig. 28. > Schrciter's form, quadrijuncta( x 700). 



Figs. 29-31. — Jthiznsolenia eriensh var. m.(irm W. & G. S. West; 

 (29) (x 1000), (30) a very smnll form (x700). (31) large 

 broad forni (x.528). 



