148 BIOLOGY OF THE RICHMOND RIVER, 



Fig. 4. — yitzschia paradoxa var. major Van Heurck (x704). 



Fig. 5. var. pcrpusilla, n.var. (xl056). 



Fig. 6. ^ vermicularis var. v'udis, n.var. (x352). 



Fig. 7. var. minuta, n.var. (x704). 



Fig. 8. — TryhlionellaEontzschiana var. minor, n.var. (x704). 



Fig. 9. — • i var. Victoria:, (Grun.) milii (x704). 



Fig. 10. girdle-view (x704). 



Fig. 11. edge in |-f ace ; much 



enlarged. 



Fig. 12. var. adidn, (Grun.) V. Heurck(x528). 



Fig. 13. var. ovata (Lagerstedt) mihi ; (a), 



girdle-view (x704). 



Fig. 14. var. nuatraUca, n.var. (x528). 



Fig. 15. ■ cnicidta, n.sp. (x704). 



Yig.lG.—Mclosira rnrians var. monilijormis (O.F.M.), semi-de- 

 tached frustules in a short filament (x704). 



Fig. 17, isolated cell dividing (x528). 



Fig. 18. — Cydotella Mcncjliiniana Kiitz., forma; (a), girdle-view 

 (x704). 



Fig. 19. var. cunccxa mihi; (a), girdle- 

 view (x704). 



Fig. 20. another form (xl().56). 



Figs.21-22. var. qiKulrata, n.var.; (22), girdle- 

 view (xl400). 



Fig. 23. var. hrcvistriata, u.var. (xl056) 



Fig. 24. ■■ var. fluviatilis, n.var. (xl056). 



Fig. 25. — Diadesmi.s confcrracea var. pereyrina (W.Sm.) (x704). 



Fig.26.—Rydrosera triquetra Wallich ( x 352) ; (a), end ( x 704). 



Fig. 27. — Coscinodiscufi lacustris var. sfellatiis, u.var. (x704). 



Fig. 28. var. dcnticulatus, n.var. (x704). 



Fig. 29.^ var. papillatus, n.var. (x352). 



Fig. 30. var. ti/mpaniformis, n.var. (x528). 



Fig.31.-- var. 7r/6(Herib.&Brun) mihi(x528). 



Plate VI. 

 (.AH figures magnified 660 diameters unless stated otherwise.). 



Fig.l. — Anahccna osciUarioidcs var. cylindracca, n.var. ; (a) fila- 

 ment diam. 7/x one end, 5/x the other, with rounded apical 

 cell, and a terminal heterocyst ; (h) terminal heterocysts, 

 two forms, ( x 1000) ; (c) filament with two forms of hetero- 

 cyst ; (d, e) cells quadrate and vacuolate, (c, d, c) show 

 plainly the development of the heterocysts from globular 

 to cylindrical; (/) spores; (g) cells with granular and 

 homogeneous protoplasm in same filament ; (h) minute fila- 

 ments like this in profusion (16), outgrowth probably of 

 isolated cells. 



