Amphipleura pellucida

Valves linear-lanceolate and very narrow, tapering gently into rounded apices. Apices are slightly constricted. Raphe branches are greatly shortened and increase in length only slightly as the length of the valve increases. A long, low-profile median rib is present through most of the valve. At the raphe branches, two longitudinal ribs surround the raphe. At the distal raphe end, a porte-crayon structure of moderate size and shape is present. A thickened nodule is not evident at the internal central area. Striae are extremely fine and visible only under optimal objective lenses and illumination in the light microscope. Well-organized longitudinal striae are also present, but are not resolvable in the LM. External distal and proximal raphe ends are straight.