PLAGIOGRAMMA PYGMÆUM GREV.
Valve linear-elliptical; pseudoraphe distinct; rows of granules transverse, usually six in each compartment, moniliform, three on each side.
Blue clay. Not common.
Pl. [10], Fig. 13.
PLAGIOGRAMMA WALLICHIANUM GREV.
Valve linear, rounded at the ends; pseudoraphe absent; transverse rows of granules, six or seven in each compartment, and two or three rows of smaller granules at each end.
Blue clay. Not common.
Pl. [10], Fig. 14.
PLAGIOGRAMMA OBESUM GREV.
Valve rhombic-lanceolate, the costæ scarcely visible; pseudoraphe rather wide; rows of granules, about seven in each compartment, slightly radiating.