Eye migration and cranial development during flatfish metamorphosis: a reappraisal (Teleostei: Pleuronectiformes)

The literature concerning eye migration and cranial development during flatfish metamorphosis is briefly reviewed and found to give rise to five hypotheses to account for the phenomenon. The cranial morphology of specimens of Soleidae, Pleuronectidae, Scophthalmidae and Bothidae in pre-metamorphic, metamorphic and post-metamorphic stages are described. The mechanisms by which eye migration and cranial development occur are discussed and some aspects of pleuronectiform relationships are briefly commented on.