Plate XXX; Figures 197 to 206; Figures 197, 205 Mag- 

 nified 500 Diameters ; all others 250 Diameters. 



Fig-. 197. Spirogyra communis (Hass.) Kiitz. page 67 

 Fig. 198. " Huviatilis Hilse . " 



Fig. 199. " " " Kept in 



dishes, the cells elongating without 



dividing, and dancing dots of oil 



appearing in the ends 

 Fig. 200. Vaucheria sessilis (?) (Vauch.) D. C. " 55 

 Fig. 201. " " " " 



Fig. 202. Spirogyra mirabilis Hass. . . "67 



Fig. 203. bcli.s (Hass.) Cleve. In 



state of decomposition ... 67 



Fig. 204. Spirogyra bellis (Hass.) Cleve . " " 



Fig. 205. iiavescens (Hass.) Cleve " " 



Fig. 206. Vaucheria. Showing sexual organs . 55 



