eye-pit

At the same time, the little sensitive spot at the bottom of the eye-pit spread out into the shape of the bottom of a cup, called the _retina_; and then the hollow of that cup between the retina and the cornea filled up with a clear, soft, animal jelly called the _vitreous humor_, and we have the eye as it is in our heads to-day.

A Handbook of Health Woods Hutchinson 1896

Like the nose pits, as they became more sensitive, they too sank in beneath the surface; but with this difference, that, instead of remaining open, the rims or edges of the eye-pit grew together and became transparent, forming a cover, or eye-glass, which became the clear part of the eye, called the _cornea_.

A Handbook of Health Woods Hutchinson 1896