Pale red sea anemone - Pale red sea anemone

A marine animal belonging to the phylum Cnidaria, class Anthozoa, subclass Hexacorallia, order Actiniaria, family Actiniidae. Also called the pink sea anemone. It is endemic to Japan, distributed south of Sagami Bay. It grows in colonies on the bony shafts of gorgonids of the subclass Octocorallia at depths of 20 meters or more. The foot disks are wide to wrap around the bony shafts of gorgonids, and since many individuals wrap around the bony shafts tightly, it may appear to form a colony at first glance, but the individuals are not connected by foot disks and are solitary like other sea anemones. The diameter and height of the body wall are both 2 to 4 centimeters, the mouth disk is wide, and the tentacles are long. It has a spear filament at the lower end of the septum, but it is significantly thicker than the spear filaments of other species and contains almost no nematocysts. It reproduces asexually by vertical fission.

[Hiroomi Uchida]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

刺胞(しほう)動物門花虫(はなむし)綱六放サンゴ亜綱イソギンチャク目ウスアカイソギンチャク科に属する海産動物。モモイロイソギンチャクともいう。相模(さがみ)湾以南に分布し、日本特産種。20メートル以深の八放サンゴ亜綱のヤギ類の骨軸上に群生する。足盤はヤギの骨軸を巻くために広がっており、多数の個体が骨軸上をすきまなく巻くために、一見群体を形成しているようにみえるが、各個体は足盤で連なることはなく、ほかのイソギンチャクと同様に単生である。体壁の直径、高さはともに2～4センチメートルで、口盤は広く、触手は長い。隔膜下端に槍糸(やりいと)をもつが、他種の槍糸より著しく太く、ほとんど刺胞を含まない。縦分裂による無性生殖を行う。

［内田紘臣］

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