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The esophagus of Eisenia foetida is either everted or retracted after anterior wounding (first eight segments removed). When everted, it forms a temporary wound covering that is probably ultimately replaced by the migrating epidermis. The plug of coelomic cells which forms around the esophagus soon after wounding is composed mainly of free coelomic cells (amoebocytes and eleocytes), with a predominance of the phagocytic amoebocytes. The fixed coelomic cells (parietal peritoneum and visceral peritoneum (chlorogogue)) make little contribution. There is little evidence for body wall muscle dedifferentiation within four days of injury, though some degradation of muscle fibers occurs. In shallow surface wounds that do not pierce the coelom epidermal basal cells and one class of cells found between the body wall muscle fibers form a plug similar to that formed by amoebocytes after anterior wounding. Structural and functional similarities indicate a relationship among these three cell types (epidermal basal cells, coelomic amoebocytes, one class of cells of the body wall), though they are normally found in different locations within the animal.

When the eight most anterior segments of Eisenia foetida are removed the wound is provisionally closed by a plug of coelomocytes surrounding an everted or retracted esophagus. Usually within one to three days the wound is definitively covered by migration of the columnar cells from the adjacent epidermis over the coelomic plug. Epidermal basal and gland cells do not directly take part in wound epithelialization. In the normal epidermis 2.3% of the cells incorporate 3H-thymidine during a labeling period of one hour. The incorporation rate for the columnar cells is higher than that for the basal cells and the gland cells are not labeled. During the period of wound covering by the epidermis (the first three days after transection) the DNA synthetic rate for basal cells and columnar cells drops steadily in both the segment bordering the wound and for at least four segments posteriorly. At four and five days the labeling rate for the epidermis of the segment near the wound rises sharply to beyond the control levels (3.7%) then drops again abruptly at six to seven days (0.8%). Two to four segments posterior to the wound the incorporation rate remains at the low 3-day level throughout the first week after transection.

Secretion by the epidermis of two oligochaetes ( Eisenia and Enchytraeus ) was investigated radioautographically following administration of 3 H-proline, 3 H-tryptophan or Na 2 35 SO 4 . Regionally epidermal columnar cells of Enchytraeus synthesize the overlying, probably collagenous, cuticle. Eisenia epidermis does not recordably synthesize the cuticle until after wounding (first eight segments removed). By two days postoperative the epidermal columnar cells of Eisenia synthesize the collagenous cuticle and, later in regeneration, the epidermis may simultaneously synthesize the different collagen of the underlying basement lamella. The epidermis of Enchytraeus . but not of Eisenia , synthesizes some sulfated material associated with the cuticle surface.