: Tracheae and spiracles in insects, book lungs in arachnids, and specialized gills in aquatic crustaceans. Subphyla Framework :
Cavity for organ development, isolates internal organs from body wall movements. invertebrate zoology lecture notes ppt new
A thick, non-cellular, collagenous outer layer secreted by the underlying epidermis. It protects against chemical and mechanical damage and must be shed through ecdysis (molting) to accommodate growth. : Tracheae and spiracles in insects, book lungs