Pl. [14], Figs. 6 and 7.
AMPHIPRORA PALUDOSA WM. SM.
Frustule membranaceous, constricted, with truncate ends. Valve linear, with acute ends. Striæ scarcely visible.
Cape May (Cleve).
Pl. [14], Fig. 5.
Tropidoneis Cleve (1891)
(tropis, a keel)
Frustule oblong, constricted in the middle; keel not sigmoid. Axial area not evident. Striæ very fine, punctate, in longitudinal lines.
TROPIDONEIS LEPIDOPTERA (GREG.) CLEVE
Valve with straight, median excentric line. Keel unilateral, projecting above the median line in zone view; central area small. Transverse striæ finely punctate. As usually seen, the valve is inclined. According to Karsten there are two chromatophores on the connective zone, each divided into four parts, each of which contains a large oval pyrenoid.