Frustule linear, truncate, dilated at the ends; zone with longitudinal folds; valve lanceolate, keel central; apices acute, with an elevated appendage; keel puncta, 5-6 in 10 µ; striæ very fine. L. 56 µ.
Atlantic City and Cape May, N. J. (Lewis).
Pl. [40], Fig. 3.
Dissipatæ
NITZSCHIA DISSIPATA (KUETZ.) GRUN.
Valve lanceolate, with sub-rostrate apices; keel excentric; keel puncta about 6 in 10 µ; striæ, 14 in 10 µ. L. 20-40 µ.
Fresh and brackish water.
Pl. [40], Fig. 7.
Sigmoideæ
NITZSCHIA MACILENTA GREG.