part of develops from start stage end stage orbital region sclerotic bone zebrafish_anatomy A pair of small dish-shaped bones that cap the anterior and posterior margin of the eyeball. The sclerotic bones also called scleral ossicles form from the scleral cartilage between the sclera and the optic choroid. The ossicles develop via unilateral perichondral ossification of the scleral cartilage from two centers opposite one another in the eye. scleral ossicle sclerotic bones TAO:0001411 ZFA:0001411 chondrocranium sclerotic cartilage endochondral bone unknown adult