Proc. Acad. Nat. Sci. Philadelphia 8(5): 163-165. Sept. 1856.

–P. 165: {"7. Manatus antiquus, Leidy [n.sp.]. / The species is predicated on fragments of ribs found in the miocene deposits of New Jersey and Virginia, and on a fragment of a rib and an isolated molar tooth, discovered by Capt. Bowman, U.S.A., in the sands of Ashley river, South Carolina. The tooth apparently corresponds to the sixth or seventh upper molar of M. latirostris, Harlan, than which it is considerably larger. It has no anterior basal ridge, but from both of the inner lobes of the crown the summits are prolonged in a curved line to the middle of the outer lobes. The specimen measures in both diameters 9½ lines."}