Pl. [21], Fig. 10.
Neidium PFITZER (1871)
(neidion, dim. of naus, a boat)
Valve linear or lanceolate; median fissures turned in opposite directions, terminal fissures appearing bifurcate (?); striæ transverse, usually oblique, finely punctate, crossed by one or several longitudinal blank lines.
Chromatophores, two, lying on the girdle side, in cell division each forming a partially divided pair. A large pyrenoid is said to be found in the middle of each chromatophore, but Mereschkowsky states that the pyrenoids are absent, but that in N. affine four elæoplasts are always seen in the centre of the frustule.
A genus easily recognized by the peculiar terminal and median fissures and by the yellowish or brownish color of the valves when dry, darker than in Caloneis.
NEIDIUM AFFINE (EHR.) PFITZER
Valve linear, with protracted, sub-rostrate or capitate ends.
Navicula affinis Ehr.
NEIDIUM AFFINE VAR. GENUINA FORMA MAXIMA CL.