Morphological studies on the ciliary muscles, lamina vitrea and ciliary vessels were made, and the results are as follows: 1. Fine fibrils and nuclei were seen in the inner sheet of the lamina vitrea. Therfore the inner sheet is not structureless, as it is generally considerd, but a fibrous membrane. 2. When the ciliary muscles contract the lamina vitrea puts pressure on the vitreous, so that the anterior chamber becomes narrow, and aquious outflow is improved. 3. When the ciliary muscles contract, the ciliary body becomes congestiv and the aquious humor is more produced. 4. When the lamina vitrea is pulled forward by the contraction of the ciliary muscles, the compression of the visual cells takes place, and anemia of the coroidal vessels occurs near the optic nerve head, so the blind sport expands.