1. KINGDOM ANIMALIA Phylum Annelida

2. Phylum Annelida Cylindrical, bilateral, & segmented True coelom
Complete digestive system
Closed circulatory system

3. Body Plan
Annelids have a true body cavity or coelom that is located between layers of mesoderm
Annelids are the first major phyla showing segmentation (metamerism) which is advantageous to movement, safety, and tagmatization

4. Feeding Annelids have a complete digestive system
Their system contains mouth, pharynx, esophagus, crop, gizzard, intestine and anus
They use muscles to help in the mechanical digestion of food

5. Movement
Each annelid segment contains its own longitudinal and circular muscles
These muscles work antagonistically, such that when the longitudinal muscles contract the circular muscles relax and the segment becomes short and thick
In contrast, when the circular muscles contract, the longitudinal muscles relax and the segment becomes long and thin

6. Reproduction
Oligochaetes are hermaphroditic and during copulation they line up facing in the opposite direction
The clitellum secretes a mucous that holds the worms in place
Later, the secretion of the clitellum acts as a cocoon where the fertilized egg develops

7. Classification Class Polychaeta (many hairs)
Class Oligochaeta (few hairs)
Class Hirudinae (leeches)