Abstract
Structure of the vomeronasal organ was investigated from the viewpoint of comparative morphology in rats, mice and rabbits by light and electron microscopy. The organ in rats and mice was round in its transverse section and encircled by the bony capsule, whereas that in rabbits was elliptical and encircled by the cartilaginous capsule. Ultrastructurally, in all these species, the surfaces of the sensory and supporting cells of the vomeronasal sensory epithelium were provided with microvilli, which seemed to accept odoriferous molecules, and lacked cilia or other surface structures. The vomeronasal respiratory epithelium lacked receptor cells and assumed a form similar to that of the nasal respiratory epithelium. Hence, the function of the former seemed to be similar to that of the latter. The venous sinus was well developed. Several layers of smooth muscles encircled the wall of the venous sinus. Elastic fibers were observed in the connective tissue lying between the venous sinus and the respiratory epithelium. Junctional specializations were developed between cells standing side by side in the respiratory epithelium. All these structures were thought to suggest the propriety of the so-called pumping mechanism. Jacobson's glands consisted mainly of mucous acini and seemed to have functions similar to those of the nasal glands which were distributed on the wall of the nasal cavity.
