1. Phylum Annelida (Segmented Worms)
15,000 Annelid species
Bilaterally symmetrical coelomates
Coelomes divided into partitions by septa
Inhabit marine, fresh water, & moist environments
Has complex digestive system
Has closed circulatory system
Epidermis is primary gas exchange organ
Are hermaphroditic
Reproduce sexually by cross fertilization
Reproduce asexually through regeneration
3 Classes

2. Class Oligochaeta Include earthworms Extracts nutrients from soils
Extremely beneficial to farming as they enrich and aerate soils

3. The Earthworm
Giant Earthworm – Amazon Basin

4. Class Polychaeta Very similar to oligochaeta Most are marine
Have paddle or ridge-like extensions on segments called parapodia
Aid in gas exchange and locomotion

5. Lugworm

6. Class Hirudinea (leeches)
Most inhabit fresh water, or moist terrestrial environments
Feed on small invertebrates or are parasitic
Have significant medicinal value in treating bruising, and as a source of Pharmaceuticals

7. The Leech