About Worms- There are more than 9,000 species in the Phyluim Annelida. These include Earthworms (Oligochaeta),Leeches (Hiradinea), a small class called Archiannelida, and the class of marine worm Polychaeta. The meaning of Polychaeta is "many bristles", and it contains over 8,000 of the 9,000 different species of Annelids

History- Although the earliest fossils are associated with the Cambrian Era, Annelids are believed to have originated in the Recambrian Era. Annelids have an enlongated body with a round cross section They have a mouth in one end (Iwhich is ocassionally jawed), and an anus on the other. Their body cavity is filed with fluid to provide support and ius also partitioned into segments.

How worms mate- Annelind reproduce both asexually as well as sexually. The earthworms and leeches tend toward hermaphroditism. Some leeches even care for their young. The polychaetes tend to have seperate sexes and reproduce by spraying their eggs and sperm into the water. Some ven have the ability to reproduce by budding. Annelids are the most common of the marine organisms. This can be seen in the sand of some beaches where there are over 32,000 burrowing in a square meter of sand.