Valve linear-lanceolate, slightly rostrate at the apices; keel puncta, 10 in 10 µ, the median not distant; striæ, 33-36 in 10 µ; zone view linear, with rounded ends. L. 25-65 µ.
Fresh water.
Pl. [32], Fig. 15.
NITZSCHIA AMPHIBIA GRUN.
Valve lanceolate, apices sometimes slightly produced, rounded; keel puncta, 8-9 in 10 µ; striæ, 16 in 10 µ. L. 20-32 µ.
Fresh water.
Pl. [32], Figs. 14 and 25.
NITZSCHIA COMMUNIS RAB.
Frustule linear, slightly attenuated at the obtuse ends; valve elliptical-lanceolate, attenuated toward the obtuse ends; keel puncta, 12 in 10 µ; striæ more than 30 in 10 µ. L. 35 µ.
Fresh water.