The digestive system of an ascarid consists of four parts: Alimentary Canal, Mouth, Pharynx, and Intestine. The alimentary canal compromises a short pharynx or esophagus representing the foregut, a long intestine or mod-gut, and a short rectum or hind gut.he stomodeum consists of the âmouth and lipsâ, buccal cavity, and the pharynx (esophagus). Each of these regions are used extensively in taxonomy as well as classification of nematodes, and for providing as indication of feeding habit or trophic group.