1. The ampullae of Lorenzini are sensitive to weak tactile stimulation applied to the ends of their jelly-filled tubes.
2. Either an increase or a decrease in their resting discharge frequency may be caused, each with an opposite after-effect.
3. ‘Adaptation’ is total, being three-quarters completed in 3-8 sec. This ‘adaptation’ probably includes accommodative changes of the tissues.
4. The function of the ampullae is discussed, but no definite conclusion can yet be reached.