Histological Development of the Vomeronasal Complex in the Pre- and Postnatal Rat

The vomeronasal complex of the rat was studied by means of different staining techniques and light microscopy between the 13th day of gestation and 42 days of postantal life. The an-lage of the vomeronasal organ in the 13-day-old embryo consisted of a cluster of cells proliferating from the olfactory placode towards the medial line. The vomeronasal organ was well developed by the end of gestation, showing the same ratio between receptor and receptor-free epithelium as in the adult animal. However, full development of the epithelia did not occur until the end of the second postnatal week. Glandular rudiments were observed within the vomeronasal area in 17-day-old fetuses, but the gland showed no sign of activity until the 7th day of postantal life, when a slight PAS-positive reaction was observed in their cells' cytoplasm. This PAS-positive reaction intensified considerably during the second week and corresponded to the adult picture by the end of this time. The content of the vomeronasal glands contrasted...