Fig. 2
The likely evolution of single-chambered eyes. Arrows indicate functional developments, not specific evolutionary pathways.
From Land and Fernald [4].
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a | Pit eye, common throughout the lower phyla. |
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b | Pinhole of Haliotis (abalone) or Nautilus. |
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c | Eye with a lens. |
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d | Eye with homogeneous lens, showing failure to focus. |
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e | Eye with lens having a gradient of refractive index. |
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f | Multiple lens eye of male Pontella. |
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g | Two-lens eye of the copepod crustacean Copilia. Solid arrow shows image position and open arrow the movement of the second lens. |
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h | Terrestrial eye of Homo sapiens with cornea and lens; Ic= image formed by cornea alone; Ir= final image on the retina. |
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i | Mirror eye of the scallop Pecten. |