The carapace is the hard shell covering of the cephalothorax of this spiny lobster.
A carapace is a hard shield, or shell covering, found over all or part of the anterior dorsal portion of many invertebrate and a few vertebrate animals. In invertebrates it is made of chitin; in vertebrates such as turtles and tortoises it consists of bone with a horny covering.
In lobsters, shrimps, crayfish, and crabs, the carapace is the part of the exoskeleton that covers the head and thorax and protects the dorsal and lateral surfaces. In many crustaceans, the term carapace is also used to describe the hard, protective covering of the cephalothorax, as that of the horseshoe crab. The carapace of a turtle's shell is composed of expanded ribs and vertebrae overlain by dermal plates and horny scales.