Clams
- Clams are invertebrates that are a part of the Mollusca phylum.
- They are protected by a hard shell made of calcium carbonate.
- They are part of the bivalve class of mollusks.
- Oxygen is absorbed into the hemolymph in the gills which provide the primary respiratory surface. The gills hang down into the mantle cavity, the wall of which provides a secondary respiratory surface being well supplied with capillaries.