There are about 42,000 species of crabs, and most of them are marine. Unlike most other arthropods, there are several species of crabs that are found on land or in freshwater. Is a crayfish a crustacean? crayfish, also called crayfish ...

Locomotion is usually obtained by the metachronal beating of the appendages. Parts such as the accessory leaves have a large surface area that acts on the gas exchange. Since most branchiopods are small with a thin cuticle, gas exchange can ...