With 23 North American species, these shells are inch to 5 inches in length. They are thick and oval to round with a radial sculpture. Some species have concentric ridges. The valves are joined by a straight hinge connected by two muscles that leave scars on the inside of each valve.
Sixty-five species inhabit North American waters. The -inch to 11-inch-long shells are oval-shaped or rounded. While some have smooth exteriors, most have radial ribs and concentric ridges that indicate the shell’s growth.
These rare and beautiful oblong shells are 4 to 8 inches long. White, with small radial ribs, they have a broad, spoon-shaped projection under the interior’s junction points. These shells may be found in North American tropical and temperate waters, but because they are so fragile, it’s rare to find one that’s still intact.
Native Pacific Oyster
These shells are 1 to 3 inches long and irregular in surface structure. The exterior is white to purple or brown with some reddish-purple. The interior is grayish white, often with a green tinge. Eight of the 50 worldwide oyster species are found in North American waters.
About 35 species of the lucine family inhabit North American waters. The white shells range from fractions of an inch to 5 inches long. A white interior is marked by an elongated muscle scar at the front end and a second rounded scar at the rear. The hinge area has two teeth in each valve.
Florida Marsh Clam
Marsh clams are found in fresh to brackish water, but only two of the 100 worldwide species live in North American waters. The thick shells are oval to circular in shape. A heavy hinge joins the halves. The surface is smooth or lightly ridged.
This ribbed shell, sometimes called a checkerboard, has red or purple spots and a white interior. It ranges in length from 1 inch to 2 inches. The scallop family includes 65 species in North America, many of which are commercially important.
The small (1/2 inch), thick-shelled, triangular-shape cardita is found from North Carolina to the Florida Keys. Its yellowish-white exterior is often marked by reddish-brown spots and 15 to 18 round, beaded radial ribs. Of the 200 species , 22 can be found on North American coasts.
About 100 species appear worldwide, 13 of those in North American waters. The thin, elongated shells may be brownish or greenish with a smooth surface. Length ranges from inch to 9 inches. Sides are parallel, and the ends are roughly square.