ABSTRACT
The retinotectal projection was mapped in 22 post-metamorphic Xenopus in which the eye under investigation had been made double-ventral by operation at stage 32. The contralateral retinotectal projection from a double-ventral eye is neither normal nor does it show the type of abnormality predicted from previous work on double-nasal and double-temporal eyes. In the case of double-ventral eyes, the nasal part of the field projection tended to be reduplicated about the horizontal midline and those field positions corresponding to latero-medial rows of electrode positions on the tectum ran ventrodorsally in the field. As the electrode rows on the tectum progressed more caudally, so the corresponding rows of stimulus positions in the field tended to curl in a temporal direction. These observations have been interpreted as indicating that the nasotemporal and dorsoventral polarities of the eye are not irreversibly determined at stage 32 and that the mechanisms generating the nasotemporal and dorsoventral axes of the eye may interact with each other.
