part_of part of epithelial system extracellular component cuticle WBbt:0005755 a rigid external coating which is secreted by the hypodermis, seam and some transitional epithelial cells which covers the outer body, the major openings into the body cavity from the exterior, and two large sensory bristles, the male spicules. The cuticle of the spicules, the hook, and of some portions of the spicule channels is especially rigid and is probably sclerotized. Similar sclerotic features are occasionally noted in the ventral surface of the male tail fan. WBPaper:00038216 exoskeleton worm_anatomy