Hermit crabs are crustaceans in the superfamily Paguroidea.
Most crustaceans are free-living aquatic animals, but some are terrestrial (e
Crustacean appendages are typically biramous, meaning they are divided into two parts; this includes the second pair of antennae, but not the first, which is usually uniramous, the exception being in the Class Malacostraca where the antennules may be generally biramous or even triramous

