ヒキガエル中耳腔の発生学的研究

抄録

This report has dealed with the development of middie ear cavity and tympanic membrane in frogs, Bubo japonicus formonsus. The middle ear cavity was formed from five to seven days after their first walking on land. The tympanic membrane was found on the surface of the temporal region of the head in about three days after the first terrestrial life. Several remarkable changes could be found at the turning point from their aquatic life to terraneous one. The subcutaneous mesenchymal tissues were absorbed and the distribution pattern of chromotophores was changed. The floor of the mouth was periodically moved up and down on their respiration. The pressure of the pharynx was thought to increase and make the pharyngeal mucosal layer extended outwards. These factors seemed to play an important role in the formation of middle ear cavity and tympanic membrane in the frog.