Pl. [26], Fig. 15.
Reported as occurring in New York Bay, but I have not seen it. The figure is from a specimen from another locality.
Minusculæ Cl.
Valve lanceolate or elliptical, chiefly distinguished by the small size; axial area indistinct; central area small; striæ radiate, very finely punctate.
NAVICULA ATOMUS NÆGELI
Valve elliptical, 6-8 µ in length; striæ radiate, 26-30 µ, closer near the ends; axial area linear, scarcely widened in the middle.
Water-troughs and ditches. Probably common, but frequently not noticed because of its minuteness. A mounting medium of the highest refractive index, such as realgar, is required to resolve the striæ. In the figure the striæ are drawn a little coarser than they appear in most specimens.
Pl. [26], Fig. 12.
Lævistriatæ Cl.
Valve lanceolate, axial area distinct; central area orbicular; striæ coarse, indistinctly punctate, approaching the costæ of Pinnularia.