The common characteristics of annelids are as follows:
- Annelids have a long cylindrical body
- The body is segmented internally as well as externally
- Bilaterally symmetrical
- Vermiform
- They are cephalopods
- They have a true body cavity
- Annelids have a gut with mouth and anus
- The body is divided into three sections. They are prosomium, truck, and pygidium
- They posses a nervous system with a nerve chord
- Posses a closed circulatory system
- No true respiratory system organs are present
- Reproduces sexually
- Can adapt themselves to most of the environments
- Some species of annelids have a pair of legs like appendages that are attached to every segment
- They have concentric nerve cell
- The head posses the sensory structure
- Annelids have a hydrostatic skeleton structure