When the snake sees, this is what the snake sees with. The snake in question is Natrix natrix, the barred grass snake. The image was “redrawn from Schwarz-Karsten, modified from original preparations.”
The labels can be translated thusly:
am- accommodatory muscle; ap- anterior pad of lens; b- brain; c- cornea; cb- ciliary body (main portion, the ciliary roll; note cross-section of hyaloid vein lying on orbiculus behind it; the very small vessels of the hyaloid plexus, lying on the inner surface of the retina, are omitted from the drawing); cr- cranium; cs- canal of Schlemm; hg- Harderian gland; io- infraocular scale; s- sclera; sm- sphincter muscle; so- supraocular scale; sp- spectacle; z- zonule (collapsed; see text).
The text in which it was printed is The Vertebrate Eye and Its Adaptive Radiation, by Gordon L. Walls, as found on archive.org. It’s got fish and rats and lizards and humans, and eyes built for night and eyes built for flying. All kinds of eyes, and what you can find inside them.