Zoology 10th Edition by Stephen Miller,John Harley

Exercise 12

The hemocoel of arthropods is an internal cavity that develops from the embryonic blastocoel and provides a cavity for their open circulatory system. The coelom of modern arthropods forms small cavities around gonads and sometimes excretory structures.
How is a hemocoel different from a coelom (see chapter 7)?
FIGURE 14.5 Events of Ecdysis. ( a and b ) During preecdysis, the hypodermis detaches from the exoskeleton, and the space between the old exoskeleton and the hypodermis fills with a fluid called molting gel. ( c and d ) The hypodermis begins secreting a new epicuticle, and a new procuticle forms as the old procuticle is digested. The products of digestion are incorporated into the new procuticle. Note that the new epicuticle and procuticle are wrinkled beneath the old exoskeleton to allow for increased body size after ecdysis. ( e ) Ecdysis occurs when the animal swallows air or water, and the exoskeleton splits along predetermined ecdysal lines. The animal pulls out of the old exoskeleton. ( f ) After ecdysis, the new exoskeleton hardens by calcium carbonate deposition and/or sclerotization, and pigments are deposited in the outer layers of the procuticle. Additional material is added to the epicuticle.