PLATE XLY. 



FIGS. PAGE 



1-3. Micrasterias Murrayi West & Gr. S. West. 1, x 



300 ; 2 and 3, x 430 . . .93 



4. M. Murrayi var. triquetra West & G. S. West. 



x 520 . . . .94 



5-6. M. truncata (Corda) Breb. x 220 . . 82 



7. Euastrum sublobatum Breb. var. dissimile Nordst. 

 x 570 (after Nordstedt). This figure (espe- 

 cially fig. 7 a of the front view) has not been 

 correctly executed . . .74 



