The carapace is large, hexagonal, and modestly convex. It has distinct areas, is usually smooth, and is wider than it is long. Six protruding teeth or spines, the longest being the last tooth, sever the anterolateral borders. The carapace and legs are usually brown to greenish-brown in appearance, but occasionally they have darker markings or mottling. Strong and typically asymmetrical, one claw on the chelipeds is typically larger than the other. The fingers of the claws are usually darker, generally with black ends. The long, flattened walking legs are designed for swimming. Swimmerets, or paddle-like appendages, are modified structures on the last pair of legs (the fifth pair) that help with swimming. The tiny eyes are protected from the elements by being brought into the orbits using long, retractable stalks. The short antennae are situated in the space between the eyes. The abdomen is clearly segmented, small, and snugly folded beneath the thorax.