Introduction of Annelida with classes

Annelida(Round segmented worm)

The animals whose body is round but segmented are called Annelida. The annelida were first included in the unsegmented worm group called Vermes which was separated by Cuvier in 1978.

                                      The word Annelida was first used by Lamarck in 1809 for higher segmented worm. The word annelida is derived from latin word annelus which means little ring. There are four class of annelida. They are

1) Polychaeta(many setae)   2) Oligochaetae (few setae)

3) Hirudinea ( leech)   4) Arachiannelida (first annelida)