Introduction to the Polychaeta

the bristleworms

Of the approximately 9000 species of annelids, more than 8000 are polychaetes. These segmented worms are among the most common marine organisms, and can be found living in the depths of the ocean, floating free near the surface, or burrowing in the mud and sand of the beach. Some, such as Eunice gigantea, may reach three meters long.

Polychaetes are known by many names: lugworms, clam worms, bristleworms, fire worms, palolo worms, sea mice, featherduster worms, etc., but all possess an array of bristles on their many leg-like parapodia -- the name polychaete, in fact, means "many bristles". The many common names reflect the wide array of body forms found in this group, unlike the earthworms and leeches which all have the same general appearance.

The delicate beauty of many polychaetes make them a favored subject for photography, and several are named after nymphs and goddesses of Greek myth, such as Nereis (the common "clam worm") and Aphrodite (the "sea mouse").

Click on the buttons below to learn more about Polychaetes.

Chaetozone is a newsletter dedicated to polychaete annelids; it is distributed electronically through the Biodiversity and Biological Collections Web Server at Cornell University.

The Wormlab Home Page has several excellent pictures of polychaetes, and a list of additional sites

You might also look at Chapter 9: Annelida of the Keys to the Invertebrates of Woods Hole for more information about the structure and kinds of polychaetes.


Buchsbaum, R. 1987. Animals Without Backbones, 3rd ed. Univ. of Chicago Press, Chicago.