Histological sections of the head of Dipsas indica . Sagittal section of the head of Dipsas indica (IBSP 73451); Paraffin section, Mallory trichrome staining (A). Transversal section of the posterior region of the head (MZUSP 16695) showing infralabial gland divided in two portions (il1 and il2) and muscle intermandibularis posterior pars posterior (ipp) associated with posteriormedial region of the il2 (shown in a higher magnification in the lower right corner); Paraffin, Hematoxylin-eosin staining (B). Higher magnification of (A) focusing the anterior part of the mandibular region to show the duct and distinct portions of il2 constituted by mucous cells anteriorly and seromucous cells posteriorly. The duct of the il2 (d-il2) is connected to the anterior region of the mouth; Paraffin section, Mallory trichrome staining (C). Transversal section of the head at the level of the eye (MZUSP 16695), showing the two portions of the infralabial gland (il1 and il2); Paraffin, Hematoxylin-eosin staining (D). Transversal section of the head at the level of the snout (MZUSP 16695), showing opening of the duct (arrow) in the floor of the mouth; Paraffin, Hematoxylin-eosin staining (E). Abbreviations: d, dentary; Hg, harderian gland; il1, lateral, mucous infralabial gland; il2, ventrolateral, seromucous infralabial gland; ipp, muscle intermandibularis posterior pars posterior; mx, maxillary; n, nasal; ng, nasal gland; ns, nasal septum; sl, supralabial gland; oc, oral cavity; p, parietal; pb, parabasisphenoid; re, respiratory epithelium. Scale bar in picture A = 5 mm; B, D and E = 500 μm; C = 1 mm. Panels at the upper right corner denote position of the section in A, B, D, C.