The differences between annelids and arthropods are given below :

Annelids

1. Animals are segmented both externally as well as internally.

2. They have unjointed appendages.

3. True coelom is well-developed.

4. Exoskeleton is absent.

5. Nephridia act as excretory organs.

6. Closed type of circulatory system is present.

7. Blood flows in closed blood vessels.

Arthropods

1. Animals are segmented externally, but not internally.

2. They have jointed appendages.

3. Blood-filled pseudocoelomic body cavity called haemocoel is present.

4. Exoskeleton made up of chitin present.

5. Green glands act as excretory organs.

6. Open type of circulatory system is present.

7. Blood flows through large sinuses.