Chapter 3 -A specimen considerably resembling the T. subundata of Sowerby, in the undulated line of the edges of the valves; but it is a much more depressed shell, and of a much less rounded form.
Chapter 5 -Branched, cylindric; pores very regular, alternate, oval, placed nearer to each other than the length of their own transverse diameters, and resembling those of an alveolite.