Polyzoary (?) forming a simple, flattened, unbranehed, two-edged frond, with sub-parallel sides, consisting of two series of cells, the bases of which rest upon opposite sides of a thin longitudinally-striated central membrane or laminar axis, from which they pass obliquely outwards in opposite directions. The cells open in longitudinal rows on the two flat or slightly convex surfaces of the frond, and have the form of more or less cylindrical tubes, which are septate or are divided transversely by a series of well-developed tabulæ. In the only species known the cells of a few of the median rows of the frond are straight, but those of the lateral rows are oblique. Cell-mouths unknown.