A study on the development of priapulids or ‘penis’ worms throws doubt on a feature that has been thought for more than 100 years to define the largest branch of the animal tree of life. Members of ...

Lynn Margulis classified the Chaetognaths, known as arrow worms, as deuterostomes. Deuterostomy is characterized by several developmental characteristics including radial, indeterminate cleavage, a ...

This is a priapulid, otherwise known as a “penis worm,” and if you click the video, you’ll understand how it earned that phallic moniker. These creatures are currently shaking the branches of the ...

Researchers have decoded two worm genomes and found that they have several genetic similarities with the vertebrates. If you were to visit a marine biology lab at the Okinawa Institute of Science and ...