The Diatomaceæ of Philadelphia and Vicinity

by Charles S. Boyer

Valve elliptical, with rounded, sub-rostrate or sub-cuneate ends; lateral areas narrow; striæ, 6 to 14 in 10 µ (Cl.), punctate. L. 50-180 µ.

Var. ehrenbergii Cl.—Lateral areas constricted in the middle, divergent at the ends. Cleve refers to Schmidt, Atlas, Pl. 2, Fig. 25, which is not divergent at the ends.

Along the coast.

Pl. [25], Fig. 10.

A narrower form occurs which has the areas divergent.

Var. ?—Valve elliptical, lateral areas narrow, convergent at the ends with short rows of punctate striæ; marginal striæ, 10 in 10 µ, punctate. L. 60 µ.

Squan River, N. J.

Pl. [20], Fig. 5.

Var. dilatata A. S.—Valve elliptical, rostrate; lateral areas convergent in the middle and nearly parallel or convergent at the ends.

Blue clay.