The Horn Shells are members of the Potamididae Family. The shells are elongated cone shaped that vary in size from small to large with a relatively small body whorl, a high spire that consists of many whorls and a relatively small aperture that has an anterior and posterior notch. They vary significantly, many are sculpted with length-wise and spiral lines or ridges; some display small varices. Most species in the Family are brownish in color.
Horn Shells are found in salt and brackish water within mud and sand flats in the intertidal zone often associated with mangrove forests. They are deposit feeders consuming algae, detritus, and diatoms from the surface of the substrate. In turn they are preyed upon by shore birds, crabs and predatory mollusks. They are similar to but differ from members of the Cerithiidae Family of Cerith Shells by having an aperture with a less-developed anterior notch. Horn Shells reside in the tropical and temperate waters of the Atlantic, Eastern Pacific and Indo-Pacific Oceans. There are approximately sixty species in the Potamididae Family of which five species are found in coastal waters of Baja.