Shell of medium size, subtrigonal, anterior view broadly cordate. Anterior end truncate, with a forward slope from the umbones to the lower anterior sharply rounded extremity. Dorsal margin behind the beaks slightly curved, with the edges of the valves incurved while in front of the beaks it is produced forward into a more or less prominent alate extension; basal margin crenate within; posterior extremity at the hinge line decidedly angular. Beaks rather prominent, gibbous, incurved. Hiatus lanceolate; occupying about two-thirds of the lower posterior margin. Surface marked by simple, regular, radiating costae, about forty in number, twenty-five of which occupy that portion of the shell behind the umbonal slope; the umbonal slope is broad, bordered on each side by a prominent costa which gives it a decided biangular appearance; the costae are crossed by numerous fine, crowded concentric lines; and a few larger somewhat imbricated lines of growth.
Proceedings of the Iowa Academy of Sciences
©1890 Iowa Academy of Science, Inc.
Keyes, Charles R.
"A New Conocardium from the Iowa Devonian,"
Proceedings of the Iowa Academy of Science, 1(Pt. 2), 23-24.
Available at: https://scholarworks.uni.edu/pias/vol1/iss2/11