Pl. [27], Fig. 15.
NAVICULA BRASILIENSIS VAR. BICUNEATA CL., FORMA CONSTRICTA
Valve oblong-elliptical, slightly constricted, with cuneate-rostrate ends; axial area narrow; central area dilated transversely and unilaterally; striæ, 9 in 10 µ; puncta closer at the border and in irregular longitudinal rows in the middle; terminal fissures small, hook-shaped, turned in the same direction. L. 93 µ.
Corresponds closely to Cleve's variety except in the constriction.
Blue clay.
Pl. [25], Fig. 2.
NAVICULA LACUSTRIS GREG.
Valve lanceolate, sub-acute; axial area narrow; central area orbicular; striæ radiate, 14 in 10 µ, punctate, the median puncta sometimes more distant than the others.
Blue clay. Rare.
Pl. [27], Fig. 12.