"a, sclerotic membrane; b, cornea; d, retina; o, optic nerve; v, vitreous humor." -Comstock 1850
"[From left to right:] Snail-shell and Egg, Ostrea and Spondylus, Carinaria, Vitreous Carinaria." —…
!["[From left to right:] Snail-shell and Egg, Ostrea and Spondylus, Carinaria, Vitreous Carinaria." — Goodrich, 1859](https://etc.usf.edu/clipart/13900/13989/mollusca_13989_mth.gif)