eyestalk
{{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 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.{{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}}]]
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. It is a common feature in nature and frequently appears in fiction.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
In nature
Eyestalks are a specialized type of tentacle. Tentacles may also have olfactory organs at their ends.{{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}} 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. Crustaceans also have eyestalks, consisting of two segments. {{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}}
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.
See also
- Eyestalk ablation
- The cephalofoils of Hammerhead sharks
References
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