PLATE X. 

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



FIG. i. Cosmarium conspersum Ralfs. 



2. " ccelatum Ralfs. 



3. ornatnm Ralfs. 



4. Ettastrum crassum (Breb.) Kuetz. 



5. Cosmarium pscudotaxichondrum Nordst. 



6. " parvulum Breb. 

 "]. hammeri Reinsch. 



8. granatum Bre"b. 



9. Euastrum verrucosum Ehrenb. 

 to. Cosmarium ochtodes Nordst. 



11. botrytis Menegh. 



12. portianum nephroideum Wittr. Front view. 

 13- " " " " End view. 



14. Closterium parvulum Naeg. 



15. venus Kuetz. 



16. Staurastrum echiitatum Pecten (Perty) Rab. 



17. Cosmarium depression (Naeg.) Lund. 



18. pulcherriimim Nordst. 



19- " " " From Kukak Bay. 



20. subcrenatum Hantzsch. 



21. pseudogrcinatum Nordst. 



22. quadrifarium Lund. 



23. Staurastrum polymorphum Breb. End view. 



24. " " " Front view. 



25. Micrasterias rotata (Grev.) Ralfs. 



26. Cosmarium broomei\sx. Thwaites. 



27. Closterium acerosum (Schrank), Ehrenb. 



28. Cosmarium bioculatum Breb. 



29. Mesot&nium braunii De Bary. 



30. Disphinrtium connatum (Breb.) De Bary. 



31. Staurastrum calyxoides Wolle. 



32. Euastrum affine Ralfs. 



33. Cosmarium constrictum Delp. Side view. 

 3-4- " " Front view. 



35- broomei Thwaites. End view. 



36- " " " Front view. 



37. Euastrum oblongum (Grev.) Ralfs. 



38. Xa nthidium 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. 



[44 s ] (212) 



