Fig. 4

3D reconstructions (a and c) of the vomeronasal organ and associated structures and transverse sections (b and d) through the snout of the grass snake embryos at developmental stage XI. a The medial aspect of the vomeronasal organ (blue) and its relation to the lacrimal duct (orange). b The connection of the lacrimal duct (orange dashed line) with the duct of the vomeronasal organ through the lateral diverticulum of the lacrimal duct (green dashed line). b’ The “connection” (arrow) between the lumen of the “orginal” lacrimal duct (orange star) and the lateral diverticulum of the lacrimal duct (green star). Magnification of the corresponding place marked by the frame in 4b, four sections posteriorly. c The ventral aspect of the vomeronasal organ and the rostral part of the lacrimal duct. The colours of the structures are the same as in the a. d The lateral part of the ventral channel. Abbreviations: A anterior, CMB cartilage of the mushroom body, D dorsal, DV duct of the vomeronasal organ, lateral eminence of the vomeronasa organ duct, L lateral, LDL lateral diverticulum of the lacrimal duct, LDV lateral eminence of the VNO duct, LTA lamina transversalis anterior, M medial, MB mushroom body, MDL medial diverticulum of the lacrimal duct, OC oral cavity, P posterior, SE sensory epithelium, V ventral, VCH ventral channel. Scale bars 20 μm (b and d); 10 μm (b’). 3D reconstructions are not scaled