Lens formation from cornea in the presence of the old lens in larval Xenopus laevis.

Three different types of experiments were carried out to investigate the role of the lens in lens-forming transformations of the outer cornea of Xenopus laevis tadpoles (at stage 51, as defined by Nieuwkoop and Faber, '56): 1) simple lentectomy; 2) incision of outer and inner cornea in the region opposite the dorsal iris without lens removal; and 3) incision of outer and inner cornea and perforation of dorsal iris without lens removal. The results indicate that the outer cornea of Xenopus laevis larvae has lens-forming competence, even in the presence of the old lens, only when direct communication has been set up between the outer cornea and the environment of the vitreous chamber. These data indicate that the inhibition exerted by the lens on lens-forming transformations of the outer cornea is mechanical in nature.