Abstract
Intra-epithelial fluid spaces in the sensory epithelium of the crista ampullaris of guinea pigs were studied with the light- and electronmicroscope. Thzse fluid spaces were found in th: intra-epithelial nerve axon just before giving rise to nerve chalices or even in the nerve chalice itself. Thus, these spaces appeared as large vacuoles in the intra-epithelial nerve axons. These axons were coming from thick myelinated nerve fibres. These spaces were usually from 1 to 5 in number and found exclusively in th: central region cf the crista ampullaris. Similar fluid spaces were sometimes detected in the nerve axons of thick myelinated nerve fibres before penetrating th: basement membrane. The nature or the mode of origin of these intra-epithelial fluid spaces and the fluid spaces within the myelinated nerve axons was discussed.