Plate XXIII: Figures 152 to 159; Figs. 152, 157, 158 

 Magnified 500 Diameters; others iooo Diameters. 



Closterium Lunula Ehrb. . . page 60 



turgidum Ehrb. . . " 



strigosum Ehrb. . 

 costatum Corda 

 Delpontei EClebs . 

 prelongum ( Breb.) Delp. 61 



lineatum Ehrb. 



A mul- 

 tiplication by division 

 Fig. 159. Closterium decorum F.reb. 



