Gomphoneis trullata

Valves lanceolate-trullate, tapering to a rounded to obtuse headpole, and more abruptly to the rounded footpole. Valves broadest below the central nodule. Striae are radiate, strongly so at the apices, more coarse around the center and more dense at the apices. Striae are biseraite. The axial area is narrow, broadening slightly to form a linear central area. One stigma, sometimes accompanied by a second stigma or isolated punctum, occur in the central area. Raphe is lateral and distinctly undulate. Longitudinal lines are submarginal in larger specimens, positioned about ½ the way between the margin and axial area in smaller specimens. Septa are very large at the headpole. Septa and pseudosepta are present at both poles.