The development of half‐eyes in Xenopus tadpoles

When the nasal or temporal half of a developing eye in Xenopus larvae between stages 32 and 38 was removed, the remaining fragment became rounded up and subsequently developed into a normal eye by mid‐larval stages. The contralateral retinotectal projection was normal in approximately two‐thirds of the animals, when mapped in later tadpole life. The remaining animals showed either some form of mirror reduplication in the visual map or else some degree of lack of order, as compared with a map taken from a normal tadpole of equivalent age. We conclude that the regulative powers of the larval Xenopus eye extend to much later stages (stage 38) than was previously thought; and a possible mechanism for the production of reduplicated maps from half‐eyes is considered.