PLATE CLXVT. 



FIGS. PAGE 



1. Staurastrum Chavesii Bohlin. x 000 (after Bohlin) 134 

 2*. St. brevispinum Breb. Zygospore X 510 . 269 



3Euastrum laticolle West. X 500 . . 264 



4.- Staurastrum Pseudosebaldi Wille. X 480 (after 



Wille) . . . . .113 



5. Desmidium gracileps (Nordst.) Lagerh. X 520 



(5e, zygospore, x 400, after Lagerheim) . 253 



6-7 D. quadratum Nordst. 6, X 520 (66, X 400, after 

 Nordstedt) ; 7, zygospore, x 400 (after Lager- 

 heim) .... 254 

 8-9.Closterium tumidum Johns, var. spkcerospora 



West. X 500 ; 8, vegetative cell ; 9, zygospore 263 

 10*. Gymnozyga moniliformis var. gracilescens Nordst. 



X 510. . . . .256 



11-13.- Eoya anglica West. 11 and 13, vegetative cells, 



X 500 ; 12, zygospore, X 500 (all after Hodgetts) 259 

 14.- -R. cambrica West, forma limnetica West. X 500 260 



