WordNet

of or relating to or resembling tentacles
any of various elongated tactile or prehensile flexible organs that occur on the head or near the mouth in many animals; used for feeling or grasping or locomotion
something that acts like a tentacle in its ability to grasp and hold; "caught in the tentacles of organized crime"
serving to sustain or support; "sustentacular cells"

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(タコ・クラゲなどの)触手;(一般に)触手のようなもの

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/05/12 14:04:04」(JST)

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Cuttlefish with 2 tentacles and 8 arms

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 "eye stalks" of various kinds of snails. Some kinds of tentacles have both sensory and manipulatory functions.

The word tentillum literally means "little tentacle". However, irrespective of size, it usually refers to a side branch of a larger tentacle. In some cases such tentilla are specialised for particular functions; for example, in the Cnidaria tentilla usually bear cnidocytes,^[1] whereas in the Ctenophora they usually bear collocytes.^[2]^[3]

Invertebrates

Molluscs

Front view of land snail showing upper and lower sets of tentacles

Abalone showing pallial tentacles

Many molluscs have tentacles of one form or another. The most familiar are those of the pulmonate land snails, which usually have two sets of tentacles on the head: when extended the upper pair have eyes at their tips; the lower pair are chemoreceptors. Both pairs are fully retractable muscular hydrostats, but they are not used for manipulation or prey capture.

Some marine snails such as abalone and top snails, Trochidae, have numerous small tentacles around the edge of the mantle. These are known as pallial tentacles.^[4]

Cephalopods such as octopuses and squids have the most spectacular tentacles. They take the form of highly mobile muscular hydrostats with various appendages such as suction disks and sometimes thorny hooks. Up to the early twentieth century they were interchangeably called "arms" or "tentacles".^[5] The modern convention however, is to speak of appendages as "tentacles" when they have relatively thin "peduncles" or "stalks" with "clubs" at their tips. In contrast the convention refers to the relatively shorter, sessile appendages as "arms". By this definition the eight appendages of octopuses, though quite long, count as arms, because they are sessile. In terms of this article however, both types of organs count as tentacles because in relevant ways they are structurally and functionally similar.^[4]

The tentacles of the giant squid and colossal squid have powerful suckers and pointed teeth at the ends. The teeth of the giant squid resemble bottle caps, and function like tiny, circular saws; while the tentacles of the colossal squid wield two long rows of swiveling, tri-pointed hooks.

Cnidarians

Cnidarians, such as jellyfish, sea anemones, Hydra and coral have numerous hair-like tentacles. Cnidarians have huge numbers of cnidocytes on their tentacles. In medusoid form, the body floats on water so that the tentacles hang down in a ring around the mouth. In polyp form, such as sea anemone and coral, the body is below with the tentacles pointed upwards. Many species of the jellyfish-like ctenophores have two tentacles, while some have none. Their tentacles have adhesive structures called colloblasts or lasso cells. The colloblasts burst open when prey comes in contact with the tentacle, releasing sticky threads that secure the food.^[6]

The tentacles of the Lion's mane jellyfish may be up to 120 feet (37 meters) long. They are hollow and are arranged in 8 groups of between 70 and 150. The longer tentacles are equipped with ctenophores whose venom paralyses and kills prey. The smaller tentacles guide food into the mouth.^[7]^[8]

Bryozoan

Bryozoa (moss animals) are tiny creatures with tentacles around their mouths. The tentacles are almost cylindrical and have bands of cilia which create a water current towards the mouth. The animal extracts edible material from the flow of water.^[9]

Amphibians

The legless amphibians called caecilians have two short tentacles, one on each side of the head, between their eyes and nostrils. The current opinion is that these tentacles supplement the normal sense of smell, possibly for navigation and to locate prey underground.^[4]

Mammals

The star-nosed mole, Condylura cristata, of North America, has 22 short but conspicuous tentacles around its nose. They are mobile and extremely sensitive, helping the animal to find its way about the burrow and detect prey. They are about 1–4 mm long and hold about 25,000 touch receptors called Eimer's organs, perhaps giving this mole the most delicate sense of touch among mammals.^[4]

References

^ Marine Species Identification Portal : Zooplankton of the South Atlantic Ocean : Glossary : tentilla. Species-identification.org. Retrieved on 2013-05-02.
^ Harmer, Sir Sidney Frederic; Shipley, Arthur Everett et al. (1906) The Cambridge natural history Volume 1, Protozoa, Porifera, Coelenterata, Ctenophora, Echinodermata. Macmillan Company.
^ Mackie G.O., Mills C.E., Singla C.L. (1988). "Structure and function of the prehensile tentilla of Euplokamis (Ctenophora, Cydippida)". Zoomorphology 107 (6): 319. doi:10.1007/BF00312216.
^ ^a ^b ^c ^d Boumis R (2013). "Animals With Tentacles". Pawnation. AOL Inc. Retrieved 2013-06-08.
^ Cooke, A. H.; Shipley, Arthur Everett et alia: The Cambridge natural history Volume 34, Molluscs, Trilobites, Brachiopods etc. Macmillan Company 1895
^ Bird J (5 June 2007). "CNIDARIANS: SIMPLE ANIMALS WITH A STING!". oceanicresearch.org. Oceanic Research Group. Retrieved 2013-06-08.
^ Kosner AW (10 July 2012). "Lion's Mane Jellyfish Image: This Is (Literally) How Things Blow Up On The Internet!". Forbes. Forbes.com LLC™. Retrieved 2013-06-08.
^ Wild Facts (29 November 2011). "Wild Fact #419 – One Large Jelly – Lion’s Mane Jellyfish". wild-facts.com. Retrieved 2013-06-08.
^ Claus N (May 2013). "Bryozoa (Ectoprocta: ‘Moss’ Animals)". els.net. eLS. John Wiley & Sons Ltd. doi:10.1002/9780470015902.a0001613.pub2. Retrieved 2013-06-08.

External links

Tentacle- About.com
Enclopaedia Britannica
Cephalopods

UpToDate Contents

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1. クラゲ刺傷 jellyfish stings

English Journal

The lateral line system in anuran tadpoles: neuromast morphology, arrangement, and innervation.

Quinzio S1, Fabrezi M.
Anatomical record (Hoboken, N.J. : 2007).Anat Rec (Hoboken).2014 Aug;297(8):1508-22. doi: 10.1002/ar.22952. Epub 2014 May 26.
Anuran larvae have been classified into four morphological types which reflect intraordinal macroevolution. At present, complete characterizations of the lateral line system are only available for Xenopus laevis (Type I) and Discoglossus pictus (Type III). We analyzed the morphology, arrangement, an
PMID 24863412

Formation of the Statolith in the Ctenophore Mnemiopsis leidyi.

Tamm SL.
The Biological bulletin.Biol Bull.2014 Aug;227(1):7-18.
The aboral sensory organ (apical organ) of ctenophores contains a statocyst with a single large statolith. The statolith comprises living cells (lithocytes), each containing a large membrane-bound concretion. The statolith is supported on the distal ends of four compound motile mechanoresponsive cil
PMID 25216498

Review of the genus Eutetrarhynchus Pintner, 1913 (Trypanorhyncha: Eutetrarhynchidae), with the description of Eutetrarhynchus beveridgei n. sp.

Schaeffner BC.
Systematic parasitology.Syst Parasitol.2014 Mar;87(3):219-29. doi: 10.1007/s11230-014-9476-5. Epub 2014 Feb 23.
The genus Eutetrarhynchus Pintner, 1913 is revised. Eutetrarhynchus beveridgei n. sp. is described from the spiral intestine of the dwarf whipray, Himantura walga (Müller & Henle) (Myliobatiformes: Dasyatidae), from the South China Sea off the Malaysian part of Borneo. The new species is charac
PMID 24563139

Japanese Journal

Distribution pattern of GFP (green fluorescent protein) in a bivalve-inhabiting hydrozoan, Eutima japonica (Leptomedusae: Eirenidae)

Kubota Shin,Nomaru Eriko,Uchida Hiroko,Murakami Akio
Journal of the Marine Biological Association of the United Kingdom 90(7), 1371-1374, 2010-07-14
… Bright green auto-fluorescence was observed in the umbrellar margin, umbrellar marginal warts, tentacular bulbs, tentacles, and manubrium of laboratory-reared immature (1–14 days old) medusae of Eutima japonica from Japan and China. …
NAID 120005439651

Sensory cells associated with the tentacular tunic of the ascidian Polyandrocarpa misakiensis (Tunicata: Ascidiacea)

Koyama Hiromichi
Zoological science 25(9), 919-930, 2008-09
NAID 40016386642

アザミサンゴの種内変異型の研究--ポリプ色彩パターン、刺胞形態、共骨密度

Wewengkang Defny S.,渡邉俊樹,日高道雄
日本サンゴ礁学会誌 9(1), 49-59, 2007
イシサンゴには色彩や群体型に種内変異を示すものが多い。沖縄のアザミサンゴでは数種の色彩変異型が報告されている。アザミサンゴは、触手のmicrobasic p-mastigophore (MpM) 型刺胞の形や共骨の密度によっても種内変異型に分けられている。色彩変異型や上記の形質に基づく変異型を詳しく記載し、それらの間の関係を調べることを目的とし、沖縄の瀬底島、残波、天仁屋の3カ所から採集されたアザ …
NAID 130004853041