1990 Volume 21 Issue 1 Pages 87-88
Development of the auditory apparatus in Bufo japonicus has been morphologically studied from early larval stages to adult stages. The table of normal development in Bufo japonicus deviced by Iwasawa was used for grouping specimens under several stages. Inner ear begins to form at the time of hatching (about stage 21-22) and is almost completed at the time of the appearance of conical hindlimbs (about St. 34-35). Formation of the operculum begins in the fenestra ovalis about the time when toes begin to develop (about St. 37) and is finished at the time when hindlimbs begin to move (about St. 41). About stage 41, the columella has began to form. By about 7 days after the first terrestrial activity, middle ear components such as columella, plectrum, middle ear cavity and tympanic membrane are formed.