The Diatomaceæ of Philadelphia and Vicinity

by Charles S. Boyer

Capitatæ.—Valve with capitate or rostrate ends; striæ radiate.

Divergentes.—Striæ strongly radiate.

Brevistriatæ.—Striæ short.

Distantes.—Striæ distant.

Tabellariæ.—Striæ radiate in the middle, strongly convergent at the ends.

Marinæ.—Marine forms.

Majores

PINNULARIA MAJOR (KUETZ.) WM. SM.

Valve linear, usually slightly gibbous in the middle and at the ends; raphe oblique; axial area less than one-third the width of valve, convergent at the ends; striæ, 7 or 8 in 10 µ, radiate in the middle, convergent at the ends, crossed by a narrow band. L. ? to 300 µ.

Blue clay. Fresh water. Abundant at Middletown, Delaware Co. (T. C. Palmer).