[Contacts of the basal processes of the visual cone cells in the outer plexiform layer of the sensory membrane of the eyeball in turtles].

In two tortoise (Agrionemys horsfieldi Gray, Testudo graeca L.) and three turtle (Emys orbicularis L., Clemmys (Mauremys) caspica Gmel, Tryonix sinensis Wieg) species, contacts of basal processes (synaptic peduncles of the cone cells) have been studied electron microscopically. Their ultrastructure and peculiarities in organization of specialized junctions between each other and with other neural elements are described. The interreceptory contacts revealed are considered to be of one of the gap junction type responsible for electrotonic interactions in the nervous system. The basal processes are shown for the first time to possess an ability to form connections on the body and on the fine branches of the tubular type horizontal cells. It correlates with a view of some physiologists on a mediated interaction of photoreceptors via the horizontal neurons.