Evaluation of melanocyte invasion in the optic cup.

For evaluation of invasive migration, the melanocytes (identified by their specific pigmentation) were filed according to the embryonic micro-compartments in which they were found in the histological serial sections: injection channel, choroid, hyaloid vessels, vitreous body, and behind the lens. “Invasive” refers to single melanocytes found in locations other than the spot of injection, invading the host tissues. “Other invasive” refers to single invasive melanocytes that were found in micro-compartments other than the listed ones.