In many species of bivalves the two portions of the shell are joined together by large and often distinct teeth that aid in holding the shell pieces together. Several teeth types are known and include cardinal teeth, pseudocardinal teeth, and lateral teeth. These are typically missing or very much reduced in the three species of dreissenids.
In many species of bivalves the two portions of the shell are joined together by large and often distinct teeth that aid in holding the shell pieces together.