Sipuncula
- Information on the classification of the peanut worms with a photograph of Phascolopsis gouldii.
- http://www.tolweb.org/Sipuncula/2487

Golfingia vulgaris
- Photograph of this sipunculid.
- http://www.marlin.ac.uk/gallery/index.php?spgmGal=Species/Sipuncula&spgmPic=0&spgmFilters=#pic

Ed Cutler's Sipuncula Research
- Includes detailed classification of the 144 species in Phylum Sipuncula.
- http://www.mcz.harvard.edu/Departments/InvertZoo/cutler.htm

Introduction to the Sipuncula
- Introduction to the peanut worms, from UCMP Berkeley.
- http://www.ucmp.berkeley.edu/sipuncula/sipuncula.html