Original: The Sipuncula or Sipunculida, sipunculid worms or peanut worms, are a phylum containing 144-320 species (estimates vary) of bilaterally symmetrical, unsegmented marine worms.
Simplified: The Sipuncula (or Sipunculida, or peanut worms) are a small phylum of marine worms. The phylum has 144 â "320 species (estimates vary) of these bilaterally symmetrical, unsegmented worms.