Zonulae occludentes in the epidermis of the snake Natrix natrix L

Zonulae occludentes of a very tight type were identified between the uppermost stratum germinativum cells of the grass snake Natrix natrix L. by means of the lanthanum tracer technique. Since zonulae occludentes alone are not capable of preventing transepithelial water flow, an additional barrier mechanism is postulated, responsible for the low rates of cutaneous water loss measured in squamate reptiles. It is suggested that the observed zonulae occludentes are involved in the sloughing process.