FRESH WATER ALG* 



PLATE XXI 



' I 1 PLEUROTCZNIUM CRENULA 



run 



' 1 PLEUROTCENIUM BREVE 



& TETMEMORUS BR^BISSONII 



1 . CLOSTERIUM LINEATUM 



' t CCKMARIUM BOTRVTIS 



F, ( . . COSMARIUM mfrlMONM. > Ft* IU COSMARIUM BROOMEI 



7. COSMARIUM TETRAOPTMAL i - ji. MICRASTERIASJENNERM 



MUM. 



I. COSMARIUM M'RGARlTiff. 

 RUM 



I? EUASTRUM ORNATUM 



- III. E DIOELTA 



- 14. E ELESANS. 



Fif If. STAURASTRUM ORBlCU 



LARE 



* 11. ST. DEJECTUM 



1. ST LEWSH. 



- JO ST PARADOXICUM. 

 ft. SI 



*. COSMARIUM SUBORBICU " IS MICRASTFRIAS TRUNCATA 



LARE ' " 16 MlCRAiTfRIAS &RANUIATA. ' .-? i 1 RAVENEILH 



" 23 ST POLYTHICHUM. 



