The cephalothorax is a body region found in certain arthropods, including spiders, crabs, and insects. It is a fused structure that combines the head and thorax, containing vital organs such as the brain, eyes, and mouthparts, as well as the legs and other appendages. In arachnids, the cephalothorax is typically covered by a hard exoskeleton called the carapace. This region plays a crucial role in locomotion and feeding, as it houses the muscles that control the movement of the legs and the mechanisms for capturing prey.