Parameter Tree:
EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES > PEANUT WORMS

Definition:
Phylum Spiuncula. Commonly called Peanut Worms, have an unsegmented fluid filled body and are characterized by a twisted intestine, the anus on the side of the body, a retractable introvert body section and a ring of tentacles around the mouth. Sipunculans have no circulatory or respiratory system

Reference:
ucmp.berkeley.edu