I. THE DEVELOPMENT OF THE ANTERIOR SEGMENT AND ITS SIGNIFICANCE FOR THE DEVELOPMENT OF THE VERTEBRATE EYE AS A WHOLE
The result of an embryologic study of the development of the anterior segment of the eye1 proved to be of special interest for the evolution of the eye as a whole and gave rise to the conceptions presented in this paper.
The development of the anterior segment of the eye is generally described as follows (fig. 1): The optic vesicle, developing from the neural tube, becomes invaginated. The primordium of the lens, lying in the surface ectoderm, also becomes invaginated ; this lens pit deepens, and finally the lens vesicle is separated from the surface ectoderm by mesoderm. In this mesoderm a cleft appears, which is the anterior chamber of the eye.
The process traced was essentially different (figs. 2 and 3): In Torpedo (fish), as soon as
. . . [Full Text PDF of this Article]