A pelecypod's shell consists of two valves, which are connected by a hinge. The valves are made of calcium carbonate and are secreted by the animal's mantle. The mantle is a tissue layer that lines the inside of the shell and is responsible for secreting the shell material.
Pelecypods have a relatively simple body plan. They have a muscular foot, which they use to move around, and a pair of gills, which they use for breathing and feeding. They also have a pair of adductor muscles, which they use to close their shell.
Pelecypods play an important role in the marine ecosystem. They are a food source for a variety of animals, including fish, birds, and mammals. They also help to filter the water and remove harmful pollutants.
Some common examples of pelecypods include:
- Clams
- Oysters
- Scallops
- Mussels