Section 1
SURIRELLA BISERIATA (EHR.) BRÉB.
Valve lanceolate, subacute at the ends; costæ robust, about 2 in 10 µ, parallel in the middle, radiate at the ends; pseudoraphe narrow. L. 100 µ.
Surirella bifrons Ehr.
Fresh water.
Pl. [39], Fig. 12; Pl. [35], Fig. 2 (smaller form).
SURIRELLA LINEARIS WM. SM.
Valve linear, with cuneate ends, slightly constricted in the middle; costæ parallel, 2-3 in 10 µ. L. 90 µ.
Fresh water.
Pl. [35], Fig. 8.