Sipuncula

Golfingia vulgaris - Photograph, description, distribution and other information on this sipunculid.
http://www.marlin.ac.uk/speciesinformation.php?speciesID=3408

Sipunculus nudus - Exercise from Invertebrate Anatomy OnLine covering the systematics, external and internal anatomy of this peanut worm.
http://webs.lander.edu/rsfox/invertebrates/sipunculus.html

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

Phylum Sipuncula - Brief description of the phylum with illustrations of a species of Phascolosoma.
http://www.meer.org/M35.htm

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

Phascolopsis gouldi - Exercise from Invertebrate Anatomy OnLine covering the systematics, external and internal anatomy of this peanut worm.
http://webs.lander.edu/rsfox/invertebrates/phascolopsis.html

Sipuncula: Peanut Worm - Provides illustrated notes on the biology of these worms.
http://www.bumblebee.org/invertebrates/SIPUNCULA.htm