PLATE XLII. 



FIGS. PAGE 



l-8.~Micrasterias truncata (Corda) Breb. 1, 3-6, and 



8, x 220; 2 and 7, x 400 . . 8JL/ 



9. M. truncata var. Bdhusiensis Wittr. x 200 



(after Wittrock) . . .85 



10-13. M. crenata Breb. 10 and 11, x 200 (after 



Ralfs) ; 12 and 13, x 520 . . 85 



U.M. Jenneri Ralfs. x 520 , 86 



