Not uncommon along the coast.
Pl. [14], Figs. 1 and 2.
AMPHIPRORA CONSPICUA GREV.
Valve linear or elliptical, with acute ends. Median line sigmoid, but the junction lines not evident. Striæ lineate, with coarser lines near the middle.
Not common. Port Penn, Delaware River.
Pl. [14], Fig. 4.
AMPHIPRORA ORNATA BAIL.
Frustule membranaceous, constricted in the middle, with well-marked folds extending from the junction line in both directions. Valve lanceolate, constricted in the middle and with protracted ends. Keel undulate on the edge.
A beautiful, transparent and delicate form, the only fresh-water species in our locality.
Delaware Water Gap, Pa.