Valve elliptical, with sub-capitate or rostrate ends; axial area narrow, central area small; striæ radiate, 12-13 in 10 µ, distinctly punctate. L. 26 µ.
Fresh water.
Pl. [26], Fig. 26.
NAVICULA GASTRUM EHR.
Valve elliptical, with rostrate ends; axial area narrow, central area transverse or irregular; striæ radiate, 9 in 10 µ in the middle. L. 26 µ.
The form here figured approaches N. anglica.
Kirkwood Pond, N. J.
Pl. [26], Fig. 25.
NAVICULA DICEPHALA WM. SM.
Valve linear, with rostrate or rostrate-capitate ends; axial area narrow, central area rectangular, transverse; striæ radiate, 12 in 10 µ. L. 32 µ.