Eyestalk

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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. Snail-front-0A.jpg
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.

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. [1] It is a common feature in nature and frequently appears in fiction. [2]

Contents

In nature

Eyestalks are a specialized type of tentacle. Tentacles may also have olfactory organs at their ends. [3] 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. [1] Crustaceans also have eyestalks, consisting of two segments. [4]

See also

Related Research Articles

Gastropoda Class of snails and slugs

The gastropods, commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda.

Banana slug Genus of molluscs

Banana slugs are North American terrestrial slugs comprising the genus Ariolimax. They are often bright yellow although they may also be greenish, brown, tan, or white.

Beholder (<i>Dungeons & Dragons</i>)

The beholder is a fictional monster in the Dungeons & Dragons fantasy role-playing game. It is depicted as a floating orb of flesh with a large mouth, single central eye, and many smaller eyestalks on top with powerful magical abilities.

Sea slug Group of marine invertebrates with varying levels of resemblance to terrestrial slugs

Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are actually gastropods, i.e. they are sea snails that over evolutionary time have either completely lost their shells, or have seemingly lost their shells due to having a greatly reduced or internal shell. The name "sea slug" is most often applied to nudibranchs, as well as to a paraphyletic set of other marine gastropods without obvious shells.

Tentacle

In zoology, a tentacle is a flexible, mobile, elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainly like muscular hydrostats. Most forms of tentacles are used for grasping and feeding. Many are sensory organs, variously receptive to touch, vision, or to the smell or taste of particular foods or threats. Examples of such tentacles are the eyestalks of various kinds of snails. Some kinds of tentacles have both sensory and manipulatory functions.

<i>Limax maximus</i> Species of slug

Limax maximus, known by the common names great grey slug and leopard slug, is a species of slug in the family Limacidae, the keeled slugs. It is among the largest keeled slugs, Limax cinereoniger being the largest.

Stalk-eyed fly Family of dipteran insects with antennae located on eyestalks

Stalk-eyed flies are insects of the fly family Diopsidae. The family is distinguished from most other flies by the possession of "eyestalks": projections from the sides of the head with the eyes at the end. Some fly species from other families such as Drosophilidae, Platystomatidae, Richardiidae, and Tephritidae have similar heads, but the unique character of the Diopsidae is that their antennae are located on the stalk, rather than in the middle of the head as in all other flies.

<i>Cornu aspersum</i> Species of edible land snail

Cornu aspersum, known by the common name garden snail, is a species of land snail in the family Helicidae, which includes some of the most familiar land snails. Of all terrestrial molluscs, this species may well be the most widely known. It was classified under the name Helix aspersa for over two centuries, but the prevailing classification now places it in the genus Cornu.

Platystomatidae Family of flies

The Platystomatidae are a distinctive family of flies (Diptera) in the superfamily Tephritoidea.

Bipolar neuron Neuron with only one axon and one dendrite

A bipolar neuron, or bipolar cell, is a type of neuron that has two extensions. Many bipolar cells are specialized sensory neurons for the transmission of sense. As such, they are part of the sensory pathways for smell, sight, taste, hearing, touch, balance and proprioception. The other shape classifications of neurons include unipolar, pseudounipolar and multipolar. During embryonic development, pseudounipolar neurons begin as bipolar in shape but become pseudounipolar as they mature.

Athoracophoridae Family of gastropods

Athoracophoridae, common name the leaf-veined slugs, are a family of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the infraorder Stylommatophora, the stalk-eyed snails and slugs. Many of the species have an attractive pattern on their dorsal surface which resembles the veins in a leaf, hence the common name.

Kerry slug Species of mollusc

The Kerry slug or Kerry spotted slug is a species of terrestrial, pulmonate, gastropod mollusc. It is a medium-to-large sized, air-breathing land slug in the family of roundback slugs, Arionidae.

Land snail Common name for many species of snail

A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. Land snail is the common name for terrestrial gastropod mollusks that have shells. However, it is not always easy to say which species are terrestrial, because some are more or less amphibious between land and fresh water, and others are relatively amphibious between land and salt water.

<i>Pomacea bridgesii</i> Species of gastropod

Pomacea bridgesii, common names the spike-topped apple snail or mystery snail, is a South American species of freshwater snail with gills and an operculum, an aquatic gastropod mollusk in the family Ampullariidae.

Slug Shell-less terrestrial gastropod mollusc

Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word slug is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly sea slugs and semislugs.

The sensory organs of gastropods include olfactory organs, eyes, statocysts and mechanoreceptors. Gastropods have no sense of hearing.

<i>Conomurex luhuanus</i> Species of gastropod

Conomurex luhuanus, common name Strawberry conch or Tiger conch, is a species of medium-sized sea snail, a marine gastropod mollusk in the family Strombidae, the true conchs. C. luhuanus is found in sandy habitat among corals in the Indopacific region. They feed on algae or detritus, move with a modified foot, and have complex eyes compared to other gastropods.

<i>Lunella ogasawarana</i> Species of gastropod

Lunella ogasawarana is a species of sea snail, a marine gastropod mollusc in the family Turbinidae, the turban snails.

Eyestalk ablation The removal of one or both eyestalks from a crustacean

Eyestalk ablation is the removal of one (unilateral) or both (bilateral) eyestalks from a crustacean. It is routinely practiced on female shrimps in almost every marine shrimp maturation or reproduction facility in the world, both research and commercial. The aim of ablation under these circumstances is to stimulate the female shrimp to develop mature ovaries and spawn.

<i>Teleopsis dalmanni</i> Species of fly

Teleopsis dalmanni, synonym Cyrtodiopsis dalmanni, also known as the Malaysian stalk-eyed fly, is a species of fly in the family Diopsidae. T. dalmanni flies possess lateral elongations on their head capsules called eyestalks. These eyestalks play an important role in mate selection and as a result physical characteristic of the fly has been the subject of several studies on sexual selection, natural selection, and mating behavior.

References

  1. 1 2 3 "Slug and Snail Anatomy". All About Slugs. Retrieved 7 December 2015.
  2. 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
  3. "Snails and Slugs (Gastropoda) – The Tentacles of Snails". The Living World of Molluscs. Retrieved 8 December 2015.
  4. Powar, C. B. (1969). "Musculature of the Eyestalk in Crustacea". Acta Zoologica: 127. Retrieved 17 August 2020.