The Diatomaceæ of Philadelphia and Vicinity

by Charles S. Boyer

May's Landing, N. J.

Pl. [34], Fig. 4.

Fig. 10, Pl. [39], is a small form from Newtown Square, Pa., in which the length is 86 µ, the costæ 5 and the striæ 16 in 10 µ.

Podocystis KUETZ. (1844)

(pous, a foot, and cystis, a bag)

Frustules cuneate, similar to Surirella, but attached by short stipes to other algæ; valve obovate.

PODOCYSTIS ADRIATICA KUETZ.

Valve nearly symmetrical, obovate, with transverse costæ about 4 in 10 µ, alternating with double rows of coarse puncta; median line distinct, linear. L. 43 µ.

Podocystis americana Bail.

Hell Gate, N. Y.