PLATE CXXXIX. 



FIGS. PAGE 



1-2. Staurastrum muricatum Breb. 1, X 520 ; 2*, X 



520 . . . . .67 



3. St. tmchygonum West. X 400 . . 50 



4. St. horametrum Roy & Biss. x 400 (after Roy 



& Biss.) . . . .51 



5. St. cristatum Nag. X 520 . . .47 



6. St. oligacantkum Breb. X 570 (after Nordstedt) 48 



7. St. oligacantkum var. incisum West. X 400 . 49 



8-9. St. echinodermum W. & G. S. West. 8, X 520 ; 



9, vertical views, X 520 . . .79 



10*. St. maamense Arch. X 510. . . 75 



11-14. &. Arnellii Boldt. X 520 . . . 79 



15. St. Arnellii var. spinifetum W. & G. S. West. X 



520 . . . . .80 



16. St. pyramidatmn West. Zygospore, X 520 . 68 



