DESMIDS, DIATOMS, AND FRESH-WATER ALG.E. 97 



the centre, the narrowest end of the wedge 

 attached to the stem (Fig. 69). 



9. EPITHEMIA TURGIDA (Fig. 70). m 

 Valves curved or bent, transverse lines 

 coarse and conspicuous (Fig. 70). 



10. COCCONEIS PEDICULUS (Fig. 71). 

 Valves oval, with a line down the cen- F ' l s- eo 



iiema acuininata. 



tre and a small nodule in the middle ; at- 

 tached by one valve to aquatic plants, especially to the 

 leaves of Andcharis (Fig. 71). 



Fig. 70. Epithemia tur- Fig. 71. Cocconfts Fig. 72. Ean6tia 



gida. pediculus. ' tetraodou. 



11. EUNOTIA TETRAODON (Fig. 72). 



Valves curved, a small nodule at each end of the 

 concave margin ; the convex border apparently scal- 

 loped, but in reality bearing four or more rounded 

 ridges (Fig. 72). 



12. PLEUROSfGMA (Fig. 73). 



Valves long S-shaped, widest in the middle and ta- 

 pering to both ends, one of which curves towards the 



