The order of the bivalves is a very large and important one.
These, of course, are closely connected with the land shells, which the bivalves are not.
The first two include Univalves and Bivalves, the last only Univalves.
Oysters, clams, and other bivalves have their eyes along the edge of the shell.
All the mollusca, except the bivalves, are provided with this radula.
As examples, we note several species of these bivalves for representation.
A great number of Bivalves are extremely regular in their form.
The dorsal valve is the uppermost in Brachiopodous bivalves.
In bivalves with two muscular impressions it passes from one to the other.
The under valve in Brachiopodous bivalves is the ventral valve.