The Diatomaceæ of Philadelphia and Vicinity

by Charles S. Boyer

Absecon, N. J.

Pl. [20], Fig. 3.

DICTYONEIS MARGINATA VAR. COMMUTATA CLEVE

Valve four and one-half times longer than broad; cells of the valve in irregular, transverse rows about 11 in 10 µ; marginal cells nearly equal, 6 in 10 µ. L. 125 µ.

Absecon, N. J.

Pl. [20], Fig. 2.

DICTYONEIS MARGINATA VAR. MAXIMA N. VAR.

Valve with cuneate segments; marginal cells, 4 in 10 µ; cells of the valve, 5 in 10 µ, obsolescent in the middle and smaller; transverse striæ, 25 in 10 µ.

Atlantic Coast. Rare.

Pl. [20], Fig. 1 (from a specimen found at Colon).