. Smell, taste, and allied senses in the vertebrates . Senses and sensation; Vertebrates. VOMERONASAL ORGAN 93 IS ered with an epithelium that resembles histologically the respiratory epithehum of the nasal cavity. This lateral epithelium may even be ciliated. The median wall is cov- ered with an epithelium much Uke the olfactory epithelium of the nose except that differentiated olfactory cells are apparently not present. The cavity of the organ ' sometimes obliterated by excessive epithelial growth and calcareous con- cretions may occur in its walls. As it appears to be without nervous con- n
. Smell, taste, and allied senses in the vertebrates . Senses and sensation; Vertebrates. VOMERONASAL ORGAN 93 IS ered with an epithelium that resembles histologically the respiratory epithehum of the nasal cavity. This lateral epithelium may even be ciliated. The median wall is cov- ered with an epithelium much Uke the olfactory epithelium of the nose except that differentiated olfactory cells are apparently not present. The cavity of the organ ' sometimes obliterated by excessive epithelial growth and calcareous con- cretions may occur in its walls. As it appears to be without nervous con- nections, the vomero-nasal organ in man is probably entirely rudimentary. 2. Comparative Anatomy. A vo- mero-nasal organ has been recog- nized for some time past in all classes of vertebrates except the fishes, but, according to Gawrilenko (1910), this group too must be admitted to have at least the foreshadowings of such an organ. Even in such primitive forms as the sharks and rays each olfactory sac is divided into two compartments with separate innervation and these two compartments may be supposed to correspond one to the vomero-nasal organ and the other to the olfactory organ proper. This double character of the olfactory apparatus is also seen in other fishes. Thus in the development of the olfactory sac of the salmon Gawrilenko has shown that this organ includes two sensory thickenings or placodes, a median one and a lateral one. These two placodes can be traced into the adult where they are said to give rise to a mediaji olfactory area and a lateral area. The median. Fig. 19.—Lateral view of the head of a human embryo showing the pore (v) of the vomero-nasal organ. After His, 1885, Fig. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Parker, George Howard, 1864-1955. Philadelphia ; London : J.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectsensesa, bookyear1922
