Ryan Photographic - Sipunculida - Peanut worms
Class/ Phylum? Sipunculida
Despite not possessing segmentation, recent DNA evidence suggests that the peanut worms belong with the Annelida rather than in the phylum Sipunculida where they had previously been placed. I leave further taxonomic placement to the taxonomists. For now I am considering them a class of the Annelida - but there are apparently subclasses of sipunculids but as I only have photos of one species I am not taking the hierarchy any further.
According to Wikipedia there are 162 species of peanut worm distributed in all the world's oceans. They range in size from 2 mm to 720 mm. They are deposit feeders and possess an extensible introvert (go figure) which has the mouth at the end. So they evert their introvert to feed and introvert their introvert when not (confused?).
Sipunculus nudus, Giant peanut worm
Sipunculus nudus, Giant peanut worm, Sea of Cortez IMG_6373. The one on the left has its introvert everted while othe one on the right has its introvert introverted (I think this is funny ...)
Sipunculus nudus, Giant peanut worm, Sea of Cortez IMG_6383