Pl. [40], Fig. 6.
Cymatopleura WM. SM. (1851)
(cuma, a wave, and pleura, a side)
Valve elliptical; surface transversely undulate, with short, marginal costæ. Frustule in zone view linear, with undulated sides.
Auxospore formation as in Surirella.
CYMATOPLEURA SOLEA (BRÉB.) WM. SM.
Valve oblong, with cuneate apices, constricted in the middle; costæ about 6 in 10 µ; striæ, 10 in 10 µ; pseudoraphe scarcely visible. L. 50-300 µ.
Blue clay. Common in the Hudson River.
Pl. [34], Figs. 8 and 9.
CYMATOPLEURA ELLIPTICA (BRÉB.) WM. SM.