 This form of digestion is used nowadays by simple organisms such as "Amoeba" and "Paramecium" and also by sponges which, despite their large size, have no mouth or gut and capture their food by endocytosis.The vast majority of other multicellular organisms have a mouth and a gut, the lining of which is continuous with the epithelial cells on the surface of the body.A few animals which live parasitically originally had guts but have secondarily lost these structures.