Valve ovate; costæ, 1½ to 2 in 10 µ; pseudoraphe linear, narrow. L. 125-200 µ.
Fresh water.
Pl. [35], Fig. 3.
S. splendida is smaller than S. robusta and wider in proportion, but, as intermediate forms occur, it is difficult to distinguish between them.
SURIRELLA ELEGANS EHR.
Valve ovate, rounded at one end and acute at the other; pseudoraphe lanceolate, narrow; costæ, 1½ in 10 µ; striæ subtle, 22 in 10 µ. Frustule in zone view cuneate. L. 180-220 µ.
Fresh water.
Pl. [36], Fig. 1.
SURIRELLA STRIATULA TURPIN
Valve broad, obovate or elliptical, rounded at each end; costæ, 1¼ in 10 µ, curved at the ends; striæ, 14 in 10 µ. Frustule in zone view cuneate; marginal alæ quite robust. L. 100-160 µ.