[Topography of the ampulla of Lorenzini system of Raja clavata and its role in electroorientation].

A detailed scheme is presented of the peripheral region of electroreceptive system of Raja clavata. These morphological data are used to calculate the overall energetic directional diagram (DD), i. e. response of the ampullary apparatus to the direction of uniform electric field strength vector. The calculations show that the overall DD of two major ampullar groups has a circular appearance. The experimentally obtained thresholds to electric stimulations determined from recordings of the vegetative reaction (respiratory reflex) are also circular. The data obtained allow suggesting that Raja clavata possesses a highly sensitive guard system capable of detecting any direction of electric field strength vector in a horizontal plane.