Final answer:
The dorsal cuticle on the head of many crustaceans forms a protective covering called the carapace, which shields the cephalothorax. Their chitinous exoskeleton, sometimes enhanced with calcium carbonate, is shed through molting for growth and development.
Step-by-step explanation:
The dorsal cuticle of the head of many crustaceans extends posteriorly to form a covering called the carapace. The carapace is a significant part of the crustacean's anatomy as it covers and protects the cephalothorax, which is a fused structure of the head and thorax. Crustaceans possess a chitinous exoskeleton, which they must periodically shed through a process called molting, followed by ecdysis, to grow or progress to the next developmental stage. This exoskeleton can be further strengthened by calcium carbonate, enhancing protection against predation and physical damage. Moreover, the circulatory system in crustaceans is open, with blood being pumped into the hemocoel by a dorsally located heart. Hemocyanin or, in some species, hemoglobin act as respiratory pigments, dissolved directly in the hemolymph.