The phylum Annelida are the segmented worms. The three main groups are the Polychaeta, such as the lugworms, some of which are free living but others living in tubes, the Oligochaeta such as the earthworm and the Hirudinea, which are the leeches. All have bodies supported by internal pressure, a hydrostatic skeleton, and are divided into segments.- Category ID : 417387
The Illinois Natural History Survey Annelida Collection is one of the largest state collections of freshwater oligochaetes in the USA, holding more than 300,000 specimens.
Provides information on this diverse phylum, the characteristics of worms, and information on the three classes, Polychaeta, Aelosomata and Clitellata.