An unsegmented burrowing marine worm with a stout body and a slender retractable anterior part bearing a terminal mouth surrounded by tentacles.
Phylum Sipuncula‘Settling near a hungry snail could be disastrous for a peanut worm, and landing too far from kelp would doom a sea urchin to starvation.’
- ‘Sipunculans, or peanut worms, have an unsegmented body with a retractable introvert.’
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