Intestine is a straight tube for most of its length. Most of the digestion and absorption of the food takes place in the intestine. The beginning of the intestine seems to be usually constant within a species. However, sometimes difficult to recognize the posterior limit of oesophagus and anterior limit of intestine especially in the badly preserved specimens. These limits can be recognized by the presence of valve at the posterior end of oesophagus. Sometimes, the internal surface of the intestine undergoes into a number of small folds and also a large folds called as typhlosole, which increases the absorptive surface of the intestine. The typhlosole differs in relative size in different species.

Fig: view of supra-intestinal glands : A. Eudichogaster prashadi ; B. Metahire birmanica

It is largest in lumbricid earthworms and absent in aquatic worms. Absence or presence, shape, anterior and posterior limits of typhlosole are of taxonomic importance. Intestinal caecae are small tubular outgrowths of the intestinal wall, their shape position, number and whether single or paired are of systematic value. Several pairs of the gland, the supra-intestinal glands are sometimes present on the dorsal wall of the intestine in successive segments at the posterior end of the typhlosole. Their absence or presence is probably of generic importance, but their number varies intra-specifically.

  Fig: Dorsal view of supra-intestinal gland in: A. Eudichogaster prashadi; B. Typhlosole in Octochaetona beatrix