The Annelida Collection at the Illinois Natural History Survey is perhaps the largest state collection of freshwater oligochaetes in the country, holding 350,000 specimens (over 7,000 lots, or collections). Approximately 225,000 specimens are permanently mounted on microscope slides; the remaining specimens are stored in alcohol in vials and jars.

With the exception of one monospecific order—Acanthobdellida (the bristle worms, restricted in distribution to the boreal regions in the Arctic)—the collection includes representatives of the other groups of worms in the phylum Annelida:

  • Branchiobdellida (one family, Branchiobdellidae—the crayfish worms, including representatives of the subfamilies Bdellodrilinae, Cambarincolinae, and Xironodrilinae);
  • Hirudinida (the leeches, including representatives of five of the six families known to occur in North America—Haemopidae, Hirudinidae, Erpobdellidae, Glossiphoniidae, and Piscicolidae);
  • the Oligochaetous Clitellata {‘Oligochaeta’}, with representatives of the aquatic microdrile oligochaete worms (families Enchytraeidae, Haplotaxidae, Lumbriculidae, Naididae {now including the subfamilies in the former family Tubificidae}, and  the former family Opistocystidae), Pristinidae, and the terrestrial megadrile oligochaetes—earthworms (families Acanthodrilidae, Glossoscolecidae, Komarekionidae, Lumbricidae, Megascolecidae, and Sparganophilidae);
  • and Polychaeta (sand worms, tube worms, or clam worms—primarily marine) including a few representatives of the families Capitellidae and Sabellidae, and the order, Aeolosomatida (one family, Aeolosomatidae—the head-crawling, or suction-feeding worms).

The INHS Annelida Collection includes representatives of many worm species that have limited known distributions in North America; however, none of the annelids known or thought likely to occur in Illinois is listed as endangered or threatened by either the federal government or by the State of Illinois, nor are any under consideration for such listing.

Pictured in the header of this page is the American terrestrial leech, Haemopis terrestris (Forbes, 1890), described (originally, Semiscolex terrestris) as new to science by Stephen Alfred Forbes [Illinois Natural History Survey Bulletin 3(VIII): 119–122] based on specimen(s) first collected from a house garden in Normal, McLean County, Illinois in April 1876.  Forbes served as director of the State Laboratory of Natural History from 1877–1917.  In 1917, he became the first director (Chief) of the newly established Illinois Natural History Survey, serving in that position until he passed away in March 1930.

[page update: 23nov2021 / 01jan;27apr2022; mjw]