(from gramma, a letter, and phoreo, I bear)
Frustules quadrangular, adnate, in zig-zag, united by an isthmus, or, usually, found free; divided by two sinuate and perforate curved septa. Valve linear or oblong, sometimes with sinuate sides, and with a pseudoraphe and transverse punctate lines.
Chromatophores granular.
GRAMMATOPHORA MARINA (LYNG.) KUETZ.
Valve linear-elliptical, with smooth apices. Septum with a wide undulation near its origin, thence straight and incrassate at the end. Striæ in quincunx, 18-21 in 10 µ.
Diatoma marinum Lyngbye.
Blue clay. Along the coast.
Pl. [8], Figs. 17 and 18.
GRAMMATOPHORA MARINA VAR. SUBTILISSIMA (BAIL.) V. H.
Valve linear, slightly constricted near the smooth apices. Septum undulated near its origin and then straight, incrassate at the end. Puncta in quincunx very subtle, 34-36 in 10 µ.