Just as there is no morphological differentiation of the fore-intestine,so also there is no histological separation into a pharynx, oesophagus, and proventriculus. The wall of the fore-intestine is made up of the following five regions listed successively from interior to exterior: (1) a chitinous inner lining, or intima; (2) a thin epithelium; (3) longitudinal muscles; (4) circular muscles; and (5) a membrane of connective tissue covering the whole fore-intestine.