PLATE XL. 



FIGS. PAGE 



1. Euastrum verrucosum Ehrenb. x 430 . 64 



2-3. E. verrucosum var. red/upturn Nordst. 2, x 520 ; 

 3, x 400 (after Nordstedt). In fig. 2 there 

 is a great reduction of the polar lobe . 65 



4. E. verrucosum var. coarctatum Delp. x 400 . 66 

 5. E. verrucosum var. coarctatum Delp. forma. 



x 400 . . . .66 



6. E. verrucosum var. (datum Wolle. x 430 . 67 

 7. E. verrucosum var. planctonicam West & G. S. 



West, x 430 . . . . 67 



8.E. Cornubiense West & G. S. West, x 520 . 70 

 9-10. E. crassicolle Lund. 9, x 400 (after Lundell) ; 



10, x 520 . . . 71 



11-13. E. insulare (Wittr.) Roy. 11, x 400 (after 



Wittrock) ; 12 and 13, x 520 . 68 



14. E. insulare (Wittr.) Roy forma . . 69 



15-18. E. crispulum (Nordst.) West & G. S. West. 



All x 520 . . . 72 



W.E. stiblobatum Breb. x 520 . . 73 



20. E. sublobatum var. subdissimile West & G. S. 



West . . . .74 



21-22. -E/. validum West & G. S. West, x 520 75 



