4 Large Clamshells and 6 Smaller Seashells. The clams are from the Tridacna genus, with one rougher and the other three smoother on top. The seashells are primarily polished pearl Turbo genus specimens, with one being a pink-mouthed specimen from the Murex genus. 

Clamshells Size: (largest) 11 1/2 X 7 X 3 in. 

#8562 . 

Seashell Size: (largest) 3 X 2 1/4 X 1 1/2 in. 

#8558 . 

A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer (exoskeleton) usually created by an animal or organism that lives in the sea. Most seashells are made by mollusks, such as snails, clams, and oysters to protect their soft insides. After the animal dies and decomposes or is eaten the empty seashells are often found washed up on beaches by beachcombers. A seashell is usually composed of calcium carbonate or chitin, and although primarily from mollusks other shells can be found that are from barnacles, horseshoe crabs, brachiopods, and even some annelid worms. The shells of sea urchins are called “tests,” and the molted shells of crabs and lobsters are called “exuviae.” While most seashells are external, some cephalopods have internal shells, making them a unique member of the invertebrate phyla. Seashells have been used by humans for many different purposes throughout history and prehistory, and today they continue to be sought after as souvenirs from a visit to a beach, or for use in art. Larger shells are often used for landscape decoration, or in aquariums, and smaller shells are frequently sold in massive quantities for use in construction, as a way to imitate the incredibly strong but pliable substance coquina, a naturally occurring sedimentary rock form by the compression of mollusk shells over millions of years.