PLATE X. 

 [Proc. Wash. Acad. Sci., Vol. Ill, PI. XLIII. 1 ] 



FIG. i. Cosmarium conspersum Ralfs. 



2. " ccelatum Ralfs. 



3. ornatum Ralfs. 



4. Euastrum crassum (Bre'b.) Kuetz. 



5. Cosmarium pseudotaxichondrum Nordst. 



6. " parvulum Bre'b. 

 y. " hammer i Reinsch. 



8. " granatum Bre'b. 



9. Euastrum verrucosum Ehrenb. 



10. Cosmarium ochtodes Nordst. 



11. " botrytis Menegh. 



12. " portianum nephroideum Wittr. Front view. 

 j, < " " End view. 



14. Closterium parvulum Naeg. 



15. " venus Kuetz. 



16. Staurastrum echinatum Pecten (Perty) Rab. 



17. Cosmarium depressum (Naeg.) Lund. 



18. " pulcherrimum Nordst. 



19 . " " From Kukak Bay. 



20. " subcrenatum Hantzsch. 



21. " pseudogranatum Nordst. 



22. " quadrifarium Lund. 



23. Staurastrum polymorphum Breb. End view. 



24. " " " Front view. 



25. Micrasterias rotata (Grev.) Ralfs. 



26. Cosmarium broomeiVar. Thwaites. 



27. Closterium acerosum (Schrank), Ehrenb. 



28. Cosmarium bioculatum Bre'b. 



29. Mesotcenium braunii De Bary. 



30. Disphinctium connatum (Bre'b.) De Bary. 



31. Staurastrum calyxoides Wolle. 



32. Euastrum affine Ralfs. 



33. Cosmarium constrictum Delp. Side view. 



34. " " " Front view. 



35. " broomei Thwaites. End view. 



36. " " " Front view. 



37. Euastrum oblongum (Grev.) Ralfs. 



38. Xanthidium antilopceum (Breb.) Kuetz. 



39. Cosmarium sexangulare Lund. 



40. " Pyramidatum Br^b. 



'Plates xliii-lxii are from drawings by Eva M. Saunders, except for plate 

 xlvi, figs, i and 2, which were drawn by Edna L. Hyatt. 



[448] (212) 



