PLATE CXLIX. 



FIGS. PAGE 



1. Staurastrum iotanum Wo lie. X 520 . . 121 



2-L St. tetmcerum Rails. 2, x 520 ; 3*, X 550 ; 4*., 



forma trigona, X 510 . . .118 



5. St. tetracerum var. validum W. & G. S. W. X 520 121 

 Q.St. micron West. X 625 . . 123 



7. St. irregulare West. X 520 . . . 150 



8. St. latiuscidum West. X 520 . . 124 



9*. . cyrtocerum Breb. X 510 . . . 135 



10. St. cyrtocerum var. compactum West. X 520 . 136 

 11. St. pseudotetmcerum (Nordst.) West. X 520 . 122 

 12. St. Chavesii Bohlin x 520 . . .134 



13. St. Pseudosebaldi var. simplicius West. X 520 . 114 

 14-15. St. Heimerlianum Liitkem. 14, X 950 (vertical 

 view, X 850) ; 15, zygospore, X 850 (all from 

 drawings by Dr. Liitkemiiller) . .165 



16. St. Heimerlianum var. spinulosum Liitkem. 



1000 (after Liitkemuller) . . . 165 



17. St. Sebaldi var. productum West. X 520 . 168 



