The digestive tract of Sabellaria alveolata (L.) is partitioned into 4 main regions: oesophagus, gizzard, intestine and rectum. Histoenzymologic study of the repartition of the protease activities along the digestive tract has shown that the proteases are secreted in the anterior intestine, where numerous serous gland cells are present. These cells display many histochemical and cytological characteristics similar to those of the gland cells previously described in digestive organs of other polychaetes. The role of the other regions of the digestive tract is discussed.