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The molluscs have the widest variety of eye morphologies of any phylum, and a large degree of variation in their function. Cephalopods such as octopus, squid, and cuttlefish have eyes as complex as those of vertebrates, while scallops have up to 100 simple eyes.

Diversity

There are between seven and eleven distinct eye types in molluscs. Molluscs have eyes of all levels of complexity, from the pit eyes of many gastropods, to the pinhole eyes of the Nautilus, to the lensed eyes of the other cephalopods. Compound eyes are present in some bivalves, and reflective 'mirrors' have been innovated by other lineages such as scallops. As well as varying in complexity, the eyes of molluscs span a huge range in size; they may be from 20 μm (0.0008 in) to 27 cm (11 in) across.

Anatomy

Gastropods and cephalopods have paired eyes on their heads (and sometimes tails), but many molluscs do not have clear head regions in which to locate the eyes. Consequently, many molluscs may have a multitude of eyes in more unlikely places, such as along the edge of their shell. Chitons have a dispersed network of tiny eyes over the surface of their shells which may act together as a compound eye. Many gastropods have stalked eyes; the eye can be retracted into the stalk itself in the presence of danger.

See also

• Arthropod eye
• Parietal eye
• Sensory organs of gastropods
• Simple eye in invertebrates
• Vision in fish
• Visual system

References

1. ^ Serb, J. M.; Eernisse, D. J. (2008). "Charting Evolution's Trajectory: Using Molluscan Eye Diversity to Understand Parallel and Convergent Evolution". Evolution: Education and Outreach. 1 (4): 439–447. doi:10.1007/s12052-008-0084-1.
2. Land, M F; Fernald, R D (March 1992). "The Evolution of Eyes". Annual Review of Neuroscience. 15 (1): 1–29. doi:10.1146/annurev.ne.15.030192.000245.
3. 'Camera eyes in gastropod molluscs", mapoflife.org

External links

Media related to Mollusca eyes at Wikimedia Commons

v t e Vision in animals
Vision	Birds Chameleons Dinosaurs Fish Toads Mammals horses dogs cats
Eyes	Arthropod eye Compound eye Eagle eye Eye shine Simple eye in invertebrates Mammalian eye human Mollusc eye cephalopod gastropod Holochroal eye Parietal eye Schizochroal eye
Evolution	Evolution of the eye Evolution of color vision Evolution of color vision in primates
Coloration	Albinism Animal coloration Aposematism Camouflage Chromatophore Counter-illumination Countershading Crypsis Deimatic behaviour Disruptive coloration coincident Eyespot (mimicry) Mimicry Structural coloration Underwater camouflage
Related topics	Animal senses Blindness in animals Eyespot apparatus Feature detection Infrared sensing in snakes Monocular deprivation Ommatidium Palpebral (bone) Pseudopupil Rhopalium Underwater vision Visual perception

• Eye
• Vision by taxon
• Mollusc anatomy