{{short description|Protrusion that extends an eye away from the body}} {{about|eyes mounted on stalks|the instinctive tendency to visually track prey|Eye-stalking}} [[File:Snail-front-0A.jpg|thumb|Pulmonate land snails usually have two sets of tentacles on their head: the upper pair have an eye at the end; the lower pair are for olfaction.<ref name="sluganatomy">{{cite web|url=http://www.allaboutslugs.com/slug-and-snail-science/slug-anatomy/|title=Slug and Snail Anatomy|publisher=All About Slugs|access-date=7 December 2015}}</ref>]]
In anatomy, an '''eyestalk''' (sometimes spelled '''eye stalk''' and also known as an '''ommatophore''') is a protrusion that extends an eye away from the body, giving the eye a better field of view.<ref name="sluganatomy" /> It is a common feature in nature and frequently appears in fiction.<ref>Allayie SA, Ravichandran S, Bhat BA. Hormonal regulatory role of eyestalk factors on growth of heart in mud crab, Scylla serrata. Saudi J Biol Sci. 2011;18(3):283-286. doi:10.1016/j.sjbs.2011.02.003</ref>
== In nature == Eyestalks are a specialized type of tentacle. Tentacles may also have olfactory organs at their ends.<ref name="tentaclesofsnails">{{cite web|url=http://www.molluscs.at/gastropoda/index.html?/gastropoda/morphology/tentacles.html|title=Snails and Slugs (Gastropoda) – The Tentacles of Snails|publisher=The Living World of Molluscs|access-date=8 December 2015}}</ref> Examples of creatures with olfactory tentacles include snails, the trilobite superfamily Asaphida, and the fly family Diopsidae. In slugs and snails, these tentacles will regrow if severely damaged, and in some species, are retractable.<ref name="sluganatomy" /> Crustaceans also have eyestalks, consisting of two segments. <ref>{{cite journal |last1=Powar |first1=C. B. |title=Musculature of the Eyestalk in Crustacea |journal=Acta Zoologica |date=1969 |pages=127 |url=https://www.researchgate.net/publication/230057681_Musculature_of_the_Eyestalk_in_Crustacea |access-date=17 August 2020}}</ref>
== Gallery == <gallery> File:Diopsid2.jpg|A stalk-eyed fly. File:Lobatus gigas eye.jpg|Well-developed eye of ''Eustrombus gigas'' on eyestalk. There is also a small tentacle on the eyestalk. File:Eyestalk of Lobster.jpg|Eyestalk of a lobster. </gallery>
== See also == * Eyestalk ablation * The cephalofoils of Hammerhead sharks
== References == {{reflist}} {{Use dmy dates|date=May 2017}}
Category:Animal anatomy Category:Eye
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