The role of the endolymphatic sac in statoconial formation and degradation

In the present investigation we studied the morphology o the endolymphatic sac in guinea pig fetuses (age 20-, 30-, 45-, 60-days-old and newborns). Twenty-day and 30-days-old guinea pig fetuses often displayed small prismatic or hexagonally shaped granules, presumably representing miniature otoconia. The granules appeared freely in the lumen of the endolymphatic sac as well as incorporated in the cytoplasm of the freely floating cells or macrophages. The origin of these "sac otoconia' as well as the possible role of the endolymphatic sac in statoconis turnover and metabolism is discussed.