Malacostraca have heads with six segments. They have a pair of antennules and a pair of antennae. They also have mouthparts. There are appendages near the mouthparts, called maxillipeds. They have five pairs of walking legs. The first pair is formed like a pincer. There are eight thoracic segments. There are six abdominal segments. They are used for swimming. Members of Malacostraca have compound stalked or sessile eyes. They have a two-chambered stomach and a centralized nervous system.