The scleral bony ring (s.b.r.) of Coturnix coturnix japonica was examined and evaluated morphometrically in its characteristic formations (scleral ossicles, overlapping sectors). The modal class 14-14, the most representative, was compared to others having minor or major numbers of ossicles with complex or simple overlaps in the left and right eyes. It was observed that the ossicles, numbered as in the literature, are ordered in a characteristic manner to form the s.b.r. The ossicle dimensions are different and numbers 4 and 7 are always smaller and larger. The s.b.r. with different numbers of ossicles compared to the model class 14-14 (0,0) showed an evident compensatory behaviour in all classes. In fact, when the ossicle number decreased, single ossicle area increased, retaining a constant s.b.r. area.
