The phylum Annelida are defined by being externally segmented, wormlike,
and have bristles (setae), although the setae may be greatly reduced in
the earthworms and leeches. The phylum is divided into four living classes:
MYZOSTOMARIA: A small group of parasitic worms parasitic or commensal
on echinoderms, particularly sea lilies. They are found only in deep water
off the North American coast.
POLYCHAETA: These marine worms vary greatly in body shape and appearance,
but all are clearly segmented externally and most have prominent bristles
and are sometimes called Bristle Worms.
OLIGOCHAETA: The familiar terrestrial and freshwater earthworms.
HIRUNDINEA: Leeches.
For a more complete description of the groups of the annelids, go
to the sites listed below.
 Introduction
to the Annelida. University of California at Berkeley Museum of Paleontology.
A great introduction to the annelids including information on their morphology,
ecology, life histories, systematics, and fossil record.
Annelid
Worm Biodiversity Resources. Geoff Read. This site contains a phylogeny
of the Annelida, a list of families, a glossary of annelid terms, and
a bibliography of references. You can also find links to other annelid
sites here.
The
World Wide Whirling Worm Web. D.L. Gustafson. This site has an excellent
introduction to the freshwater and terrestrial annelids of North America,
particularly for Montana.
Tree
of Life - Annelida. A classification of the annelid worms.
Animal
Diversity Web. A short introduction to the annelids.
A
Primer on the Invertebrates. Larry T. Spencer. Short introductions
to the polychaetes and oligochaetes.
Center
for Annelid Resources. Mark Wetzel, Illinois Natural History Survey.
Checklists of the aquatic and terrestrial annelids of Illinois may be
found at this site as well as an extensive bibliography.
HIRUNDINEA (LEECHES)
Tree
of Life - Hirundinea. M. Siddal and E. Burreson. This is a great site
with an introduction to the leeches, their phylogeny and systematics,
morphology, and references. You will also find a gallery of leech photographs,
a classification, and information about their life histories and evolution.
OLIGOCHAETA (EARTHWORMS)
Frequently
Asked Questions about Earthworms. Alan Tomlin. This site has frequently
asked questions about earthworms and also includes a couple of photographs.
The question at the top of this page came from here.
Nick
Musurca's Earthworm Web Page. A very nice, non-technical site by a
student on the morphology, reproduction, and general biology of earthworms.
Earthworms.
John Mertus. An excellent, non-technical introduction to the earthworms.
Building your Soil. Organic Online. The effects of earthworms in conditioning
and enriching soil.
POLYCHAETA (MARINE WORMS)
Keys
to Marine Invertebrates of the Woods Hole Region. Marine Biology Laboratory.
This site has an introduction to the marine annelids, a note on polychaete
terminology, and a key to the families and species of polychaetes found
in the Woods Hole region of Massachusetts.
Marine
Biology Laboratory Specimen Database. A collection of photographs
of marine annelids from the Woods Hole region of Massachusetts.
Annelid
Systematics and Taxonomy. This site contains a world list of polychaete
families and their higher classification.
British
Columbia Creature Page. Photographs and some information on four species
of marine annelids found in British Columbia waters. |
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