The Diatomaceæ of Philadelphia and Vicinity

by Charles S. Boyer

Pavonia, N. J., artesian well.

Pl. [26], Fig. 9.

Bacillares Cl.

Valve linear or linear-elliptical, with broad ends; axial area narrow, the median line enclosed in siliceous ribs; striæ finely punctate, more distant in the middle.

NAVICULA BACILLUM EHR.

Valve linear, with rounded ends; axial area enclosed in siliceous ribs and slightly expanded on each side at the ends; terminal nodules incrassate; central area small, elliptical; striæ, 15 in 10 µ in the middle, transverse, distinctly punctate, closer at the ends L. 47 µ.

Fresh water.

Pl. [26], Fig. 10.

Cleve describes the form as having slightly radiate striæ in the middle. There is considerable difference in the descriptions of Cleve, Donkin, Grunow and Van Heurck, as also in all of the figures.

NAVICULA AMERICANA EHR.