Mollusc eye

The molluscs have the widest variety of eye morphologies of any phylum,^[1] 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.^[2]

There are between seven and eleven distinct eye types in molluscs.^[3] 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.^[1] 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.^[1]

Gastropods and cephalopods have paired eyes on their heads (and sometimes tails),^[1] 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.^[1] Chitons have a dispersed network of tiny eyes over the surface of their shells which may act together as a compound eye.^[1] Many gastropods have stalked eyes; the eye can be retracted into the stalk itself in the presence of danger.^[1]

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

Media related to Mollusca eyes at Wikimedia Commons

• Eye
• Vision by taxon
• Mollusc anatomy

• Commons category link is on Wikidata