The Development of Specialized Chromatophores and a Changeable Light Filter in the Cornea of the Sculpin Porocottus allisi

The development of corneal staining cells (CSCs) and a changeable light filter made of CSCs was studied in the sculpin Porocottus allisi(Cottidae). It is shown that CSC development is complete within 9 days, and the whole changeable light filter system, within 11 days. The development begins with the droplike chromatophore stage. Later on, numerous processes and a projection towards the pupillary zone are formed, accompanied by the appearance of granular structures in the cytoplasm. In subsequent development, the cell becomes round. Later on, it becomes lanceolate, forming a single process extended towards the pupillary zone. On day 3 of development, the process is relatively short and wide. Beginning from this moment, the cell responds to changes in illumination. Light filter formation starts in the dorsonasal cornea and expands dorsally, ending in the ventral cornea 6 days after beginning. The end of light filter development coincides with the metamorphosis of the larvae, which is consistent with the peculiarities of their ecology.