otocyst

The structure formed by invagination of the embryonic ectodermal tissue that develops into the inner ear.

A statocyst.

In zoology, an auditory vesicle; any cavity or cyst which contains the essential parts of an organ of hearing; especially, the auditory vesicle or capsule of some of the Invertebrata, often containing otoliths, and subservient to the function of audition.

An auditory cyst or vesicle; one of the simple auditory organs of many invertebrates, containing a fluid and otoliths; also, the embryonic vesicle from which the parts of the internal ear of vertebrates are developed.

An organ involved in balance and orientation.

The precursor of the inner ear.