exoskeleton

1. (anatomy) A hard outer structure that provides both structure and protection to creatures such as insects and Crustacea.Examples: "This is the case not only with all forms provided with exoskeleta and endoskeleta, into the composition of which lime largely enters, but also with those which exercise the precipitating effect on the calcium salts they absorb from sea water, the precipitation rarely going so far as to form a distinct deposit in the cells or tissues of the organism."; "Ordinarily, allergy to animals is due to either their fine dander which becomes aerosolized or to the exoskeleta, pupae, or feces of their ectoparasites."; "After separation, the next generation of daughters resumes the photosynthetic fixation (reduction) of carbon, the sequestration of phosphorus, nitrogen, and mineral nutrients (up to a score), and the synthesis of the proteins that will contribute to the generational doubling of biomass. Structures such as flagella, scales, and exoskeleta also have to be reallocated or copied."