in size as the animal grows. Therefore, the animal periodically sheds the external part of the cuticle in a process called moulting or ecdysis. As the time for moulting approaches, as much as possible of the exocuticle material is internally digested by enzymatic action and reabsorbed through the epithelial layer. As its base gets dissolved away, the old cuticle begins to separate from the epidermis in a process called apolysis. Early in the process of apolysis the epithelial cells release enzymatic moulting fluid between the old cuticle and the epidermis. The enzymes partly digest the endocuticle and the epidermis absorbs the digested material for the animal to assimilate. Much of that digested material is re-used to build the new cuticle. Once the new cuticle has formed sufficiently, the animal splits the remaining parts of the old integument along built-in lines of weakness and sheds them in the visible process of ecdysis, generally shedding and discarding the epicuticle and the reduced exocuticle, though some species carry them along for camouflage or protection. The shed portions are called the exuviae. The animal then expands its body by swallowing liquid or gas and in the process it stretches the new integument to its proper size and shape. The new integument still is soft and usually is pale, and it is said to be teneral or callow. It then undergoes a hardening and pigmentation process that might take anything from several minutes to several days, depending on the nature of the animal and the circumstances. References Cuticle