2. Mouth

3. Retracting muscles

4. Gonads

5. Acontial filaments

6. Pedal disk

7. Ostium

8. Coelenteron

9. Sphincter muscle

10. Mesentery

11. Column

12. Pharynx

Sea anemones have soft tube like bodies. The external structure consists of the tentacles, the oral disk, and the pedal disk. can be found.The tentacles, which are covered in nematocysts, capture and transport prey to the oral disk. The oral disk serves as both the mouth and the anus. The mouth is the opening to the coelenteron, a single sac like cavity that performs all digestive functions. The pedal disk attaches the sea anemone to hard surfaces. The internal structure of a sea anemone consists of the contracting muscles, the gonads, the acontial filaments, and the ostium. The retracting muscles consist of simple longitudinal fibers that contract to move the anemone vertically. The sphincter muscles allow the tentacles to close over the oral disk. The gonads can be found in the mesentery. The ostium are where water is let in and out of the anemone. The acontial filament are found in the bottom sac section of the coelenteron. The acontial filaments are laden with nematocysts. Acontia filaments are used for protection from predators.