Figure 4.

Scheme of regeneration of anterior part of digestive system after anterior evisceration. (a) Anterior part of holothurian just after evisceration; (b) Longitudinal section of the region of the mesentery, which is marked by the rectangle in (a). (c) Transverse section of the region of mesentery which is marked by solid line in (b). (d) Anterior part of holothurian on third day post-evisceration; (e) Longitudinal section of the region of the tissue thickening, which is marked by the rectangle in (d). (f) Transverse section of the region of connective tissue thickening which is marked by solid line in (e). (g) Anterior part of holothurian on seventh day post-evisceration; (h) Longitudinal section of the region of gut anlage, which is marked by the rectangle in (g). (i) Transverse section of the site of embedding of coelomic epithelial cells into connective tissue thickening which is marked by solid line in (h). ab, aquapharyngeal bulb; bw, body wall; ce, coelomic epithelium; ct, connective tissue; ctt, connective tissue thickening; dc, de-differentiated coelomic epithelial cell; dm, de-differentiating myoepithelial cell; dp, de-differentiating peritoneal cell; ga, anterior gut anlage; m, mesentery; my, myoepithelial cell; nc, nerve cell; pc, peritoneal cell; sls, myofilaments grouped into spindle-like structures, tc, coelomic epithelial cell during transdifferentiation.