Figure 3

Longitudinal cuts of the digestive system of O . bimaculatus paralarvae at 0 DPH. A and B, location of the organs that integrate the digestive system in the internal cavity of the mantle. C, buccal mass. D, radula. E, detail of the anterior salivary gland. F, esophagus embedded in the cartilaginous structure of the paralarvae head. G, detail of the secretory tubules of the posterior salivary gland. H, augmentation of the duct that communicates to the two sections of the posterior salivary gland with the buccal mass cavity. I, detail of the crop structure. J, approach of stomach epithelium. K, structure of caecum epithelium. L, appendix of the digestive gland. M, secretory tubules of the digestive gland. N, intestinal epithelium. A, arm; ADG, appendix of the digestive gland; ASG, anterior salivary gland; BM, buccal mass; C, caecum; Ci, cilia; CCBN, columnar cells with basal nuclei; CM, circular muscle; Cr, crop; CSC, cubical secretory cells; CT, connective tissue; DG, digestive gland; DPSG, duct of the posterior salivary gland; E, esophagus; EPFC, epithelium of pseudostratified flat cells; H, head; I, intestine; L, lumen; MC, mucous cells; Ma, mandible; Od, odontophore; PCE, pseudostratified columnar epithelium; PSG, posterior salivary gland; R, radula; S, sine; SEC, simple columnar epithelium; SM, smooth muscle; SFCE, simple epithelium of flat cells; St, stomach; T, teeth; Tu, tubule.