Characteristics of Phylum Ctenophora

1. All members of the phylum Ctenophora are marine and never form a colony.

2. No polyp stage is found but its characteristics are found only in the embryo or in the adult.

3. Locomotion is by cilia, cilia are united to form a comb plate.

4. There are eight comb plates arranged in median rows.

5. Tentacles when present are two, one lies opposite to the other per radius.

6. Tentacle is contractile and can be withdrawn within a sac.

7. One straight alimentary canal opens outside through the stomodaeum.

8. Body has two poles, the oral and the aboral pole.

9. Alimentary canal is divided into many canals to form the canal system.

10. One axial canal is extended up to an aboral pole and opens outside through two excretory pores.

11. Gastric filaments are absent.

12. Sense organ one and present in the aboral pole.

13. There is no alternation of generations in the life cycle, in some case metamorphosis is found.