Family Carditidae

Shell size to 7 mm; shell small, narrow, triangular. Sculpture of 12-15 ribs squarish in cross-section. Interspaces much narrower. Umbo not central, displaced to the side. Color whitish or pinkish with brown chevron-like markings. Interior of valves mostly brown.

Shell size to 6 mm; shell small, inflated, triangular. Sculpture of 15 to 18 strongly-beaded radial ribs. Umbones pointing forward. Three hinge teeth, usually stained purplish-blue. Color grayish-brown to bright-pink, at times with brown mottlings.

Shell size up to 6 mm (0.24 inch). Shell shape quadrangular, with sharp, beaded radial ribs, margin finely notched (crenulated), as a result of the presence of ribs. Color white with small, faint pink or orange spots. Do not confuse with the more "triangular," close relative Three-tooth Carditid, Pleuromeris tridentata, or commonly found juveniles of the Broad-ribbed Carditid, Cardites floridanus, which are more asymmetrical, with the umbo placed in a more anterior position. (The inside of the valves may look "dirty," and viewers may think that curatorial staff at the National Shell Museum didn't care to clean the shell prior to photography. The dried gunk, however, are remnants of the mollusk soft parts that may yield genetic information in the future, so it stays. Photos by James F. Kelly.

Shell size to 40 mm; shell thick, solid, heavy, ovate. Sculpture of about 15-20 thick radial ribs crossed by concentric lines, which gives scaly appearance to ribs. Umbos close together. Lunule small. Color yellowish-white with blotches of reddish purple to brown. Interior white. Attaches by byssus to hard substrates. Common on mud flats. The yellow-tinged white-shelled color variant shown in image 2 is infrequently found on the barrier islands of Collier County. This shell was collected by Amy Tripp on Kice Island. The composite image to the right shows a juvenile specimen measuring about 9