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The vomeronasal complex of 5 different aged pig embryos Sus scrofa dom. Linnaeus, 1758 with a total length (TL) of 330, 180, 75, 50 and 45 mm respectively were studied. In all cases the nasopalatal part surrounding Jacobson's organ was generally established. During the studied period of development the completion of details within the cartilaginous supporting structures were of primary interest. In the youngest embryo studied, ducts and furrows of the vomeronasal complex were blocked by fused epitheliums. Their dissolvement was completed in an embryo of 57 mm (TL). The elaborated vomeronasal complex of the oldest embryo allowed some further analyses. So it proved that all morphological peculiarities of the supporting structures, the nasopalatine ducts and the papilla palatina in pigs are an indication of their importance to a properly functioning vomeronasal complex. As pigs have no rhinarium or cleft snout of the kind found in most mammals, no philtrum communicates with the sulcus papillae palatinae and the nasopalatine ducts where Jacobson's organs merge into. Their flat snout is however provided with a dinstict ventral groove which is obviously a substitute for the missing philtrum. Generally it was possible to classify the vomeronasal complex in S. scrofa from a phylogenetic point of view. As this anatomical system in placental mammals fundamentally reveals two differing construction types, classified as either primitive or progressive S. scrofa possesses a progressively developed vomeronasal complex.

Tear secretions discharged by the Harderian gland are suggested to function as a solvent for molecules sensed by the vomeronasal organ (VNO) in anurans. It has been assumed that chemical stimuli are absorbed at the surface of the eye to be carried -together with the lacrimal fluid -into the nasal cavity via the nasolacrimal duct. In the study presented herein, we examined the intranasal anatomy of 10 different anuran species to analyse the opening region of the nasolacrimal duct and its functional relationship with the VNO and the external naris. In addition, vital staining of the nasal cavities was conducted. Our results indicate that stimuli reaching the VNO are more likely to be ingested through the nostril than via the eye. In many cases the intranasal orifice of the nasolacrimal duct shows a close proximity to the external naris and simultaneously we observed a noticeable distance to the VNO. We suggest that the secretions of the Harderian gland are carried to the external naris by the nasolacrimal duct, where they bind chemical stimuli that are subsequently actively transported into the VNO. In some of the investigated species the opening region of the tear duct was situated in a more caudal part of the nasal cavity and closer to the VNO. In these cases a conspicuous system of channels can be found, which is suspected to carry the intruding medium of smell from the nostril to the nasolacrimal aperture.

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