Histological and ultrastructural observations of the attachment between the oral cavity of the fetus and the nipple of the mother in opossum (Didelphis azarae).

The mechanism of fixation of the fetus to the maternal nipple of opossum (Didelphis azarae) was studied in fetus of different ages through histological sections of the oral cavity keeping the nipple inside it. No organic connection was found between the maternal nipple and the tissues of the fetus. The increase of the nipple volume inside the oral cavity of the fetus and the imbrication between the corneous extracts of the nipple, palate and tongue epitheliums increase the fixation strength and contribute to the act of suckling.