PLATE LXI. 



FIGS. PAGE 



1-2. Cosmarium inconspicuum West & G-. S. West. 



x 520. 2, zygospore . . .164 



3-7. C. Uoculatum Breb. 3-6, x 520; 7, x 400; 



5-7, zygospores ; 7, after Kalfs . .165 



8-9. C. bioculatum forma depressa Schaarschm. 8, 



x 800 (after Schaarschmidt) ; 9, x 520 . 166 

 10-11. C. bioculatum var. liians West & G. S. West. 



x 520 166 



12-15. C. tenue Arch. 12, 14 and 15, x 400; 13, 



x 600 . . . . 167 



16-18. C. tinctum Kalfs. 16, x 600; 17 and 18, zygo- 



spores, x 400 (after Ralfs) . .168 



19-20. C. tinctum var. intermedium Nordst. 19, x 



520; 20, x 570 (after Nordstedt) . . 169 



21-22. C. flavum Roy & Biss. x . 400 (after Roy). 



22, zygospore . . . .170 



23-25. C. contractual Kirclin. 23, x 500; 24 and 



25, x 400 . . . 170 



26. C. contraction forma Jacobsenii (Roy) West & 



G. S. West, x 400 (after Jacobsen) . 171 



27. C. contractual var. Gartanewse West & G. S. 



West, x 520. . . .173 



28. C. contractual var. ellipsoideum (Elfv.) West & 



G. S. West, x 500 (after Elfving) . 172 



29. C. contraction var. ellipsoideum forma retusa 



West & G. S. West, x 520 . .173 



30-32, C. contractual V&Y. ellipsoideum forma (1). x 520 173 



33. C. contractual var. ellipsoideum forma (2). x 520 173 



34. Zygospore of C. contraction. x 400 . 171 



35. Zygospore of C. contractual var. ellipsoideum. 



x 400 (after Liitkemiiller) . .172 



36-37. C. subcontractum West & G. S. West, x 400. 174 



38. C. subaversum Borge. x 740 (after Borge) . 174 



