INTRAOCULAR VASCULARIZATION IN SOME FISHES

In the elasmobranchs, no vessel is found either in the vitreous cavity or on the retina. The iris artery proceeds through the ventral choroid and sends off a branch to the small lens muscle papilla. Most occurrences in the teleosts are classified into four types: the higher falciform process, the low falciform process, the low falciform process with branches on the retina, and the vitreal vessels, depending upon the vascular development of the hyaloid artery either in the vitreous cavity along the persisting embryonic fissure or onto the retina. In the vitreal vessels type, the numerous branches on the retina join a peripheral annular vessel, while the main vessel proceeding from the optic disc to the lens muscle tends to be indistinct. In the holosteans, the arterial entry near the ventral ora is associated with the ventralward elongation of the optic disc. In the Actinopterygii, vascularization of the falciform process type may have arisen because the vitreal vessels type is affected by the development of the accommodatory lens muscle.