Tentacles
can refer to the elongated flexible organs that are present in some animals, especially invertebrates, and sometimes to the hairs of the leaves of some insectivorous plants. Usually, they are used for feeding, feeling and grasping. Anatomically, they work like other muscular hydrostats.
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TENTACLES TICKETS
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Tentacles in invertebrates
The phylum
Mollusca includes many species with
muscular hydrostats in the form of tentacles and arms.
Octopus tentacles are usually called
arms. Tentacles are distinguished in this context as being longer than arms, with suckers at their tips only.
Squid and
cuttlefish have eight arms like octopuses, and also two tentacles.
The tentacles of the
Giant Squid and
Colossal Squid are particularly formidable, having powerful suckers and pointed
teeth at the ends. The teeth of the Giant Squid resemble bottle caps, and function like small,
circular saws; while the tentacles of the Colossal Squid wield two long rows of swiveling, tri-pointed hooks.
Snails are another class of
Mollusca. They have far less elaborate tentacles than the
Cephalopods. Pulmonate land snails usually have two sets of tentacles on the head: the upper pair have an eye at the end; the lower pair are for
olfaction. Both pairs are fully retractable. Some marine snails such as the
abalone and the top snails,
Trochidae have numerous small tentacles around the edge of the
mantle. These are known as pallial tentacles.
Cnidarians, which include among others the
jellyfishes, are another phylum with many tentacled specimens. Cnidarians often have huge numbers of
cnidocytes on their tentacles. Cnidocytes are cells containing a coiled thread-like structure called a
nematocyst
, which can be fired at potential prey.
Many species of the jellyfishlike
ctenophores have two tentacles, while some have none. Their tentacles have adhesive structures called
colloblasts or lasso cells. These cells burst open when prey comes in contact with the tentacle; sticky threads released from each of the colloblasts will then capture the food.
Bryozoa (Moss animals) are tiny creatures with a ring of tentacles surrounding the mouth.
Tentacles in amphibians
Some wormlike
amphibians have tentacles. The
caecilians have two tentacles at their heads, which are probably used for smell.
Tentacles in mammals
The
star-nosed mole,
Condylura cristata
, possesses nasal tentacles which are mobile and extremely sensitive, helping the animal to find its way about the burrow and detect prey.
Tentacles in plants
In
carnivorous plants, tentacles refer to the stalked glands of the upper surface of the
leaves.
On a
sundew plant, they are hairlike projections with a drop of nectar-like glue which attract insects. When an insect is captured, the tentacles bend inward and the leaf rolls together as shown in the picture. The tentacles then secrete
enzymes to dissolve and digest the insect.
Tentacles in cultural context
Tentacles appear in legend and fiction, often in a negative or violent context. For examples, see:
- Tentacle rape
- Purple Tentacle (see Day of the Tentacle)
- Cthulhu
- The Kraken
- Cecaelia
In games
- Half-Life
- Die by the Sword
- Ing
- Day of the Tentacle