The planar are flat worms free swimmers or crawling. Species live at sea, others out of fresh water, until in the grounds very humides.

Appearance

Seldom larger than 2 to 4 cm, they are fine like paper with cigarette.
Like the nudibranches, their colorings are very variées.
But they are different outside from the Nudibranche S by the absence of Branchie and the very low thickness of their corps.
They are very fragile, it is better to avoid handling them.

Specificities

  • They do not have an anus and eliminate part of their rejections by Osmose.
  • They do not have a Branchie S and also breathe by osmosis.
  • They move thanks to cilia, invisible with the naked eye which recover their body.

Reproduction

The planar ones have an astonishing mode of reproduction: They are Hermaphrodite S, i.e. they have a male genital apparatus and a genital apparatus female. However fecundation is generally cross (not autofecondation). Certain planar have another characteristic: their genital apparatus female does not give on outside. The copulation of two individuals thus returns to a reciprocal perforation to deposit Gamète S males. One speaks about “fertilization crossed” by “insemination Hypodermique”.

Regeneration

The capacities of regeneration of planar are extraordinaires.
If part of planar is separated from the remainder from the body, it will recreate in its entirety the other part manquante.
For more information on the capacities of regeneration

Taxonomy

Super-junction

Oddly the worms are regarded as a super-embranchement.
Junctions being: the Annélide S (Annelida), Sipunculien S, Némerte S, Acanthocéphale S, Phoronidien S, Nematode S (Nematoda) and finally the Plathelminthe s.

Junction

The junction of the Plathelminthe S (flat + helminths = worm) contains primarily classes of parasites:
  • Cestode S (Cestodoa) (Towards internal parasites the vertebrate ones.)
  • Cestodaire S (Cestodaria)
  • Monogène S (Monogenea) (Towards Parasites of fresh water fish)
  • Temnocephale S (Temnocephalida)
  • Trematode S (Trematoda) (Towards Parasites the vertebrate ones)
But also the class which interests us:

Classify

The Class of the Turbellarié S (Turbellaria) contains free Verse marine swimmers or of fresh water having a skin cilié.
It contains the orders of the Acoelle S, RhabdoCoelle S, Polyclade S and Triclade S.

Order

The order of the Triclade S (Tricladida) differ from the others turbellariés mainly by the size which is higher, but also by the morphology which is more “punt”. The order of the Polyclade S also seems to correspond to the planar ones.

Kind

The Planaria Kind contains among the most coloured species accessible to the plungers.

See too

  • Plathelminthe
  • a very complete French site on planar the
  • the site of Zoology of the University of Ottawa
  • Some superb photographs
  • All colors of planar

Simple: Turbellaria

Random links:Rene Diehl | List horse-drawn vehicles | Orbifold | Living room of May | Joachim Hansen