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What Are Functions of the Starfish Ventral View?

Starfish is the common name for sea stars, a member of the echinoderm phylum. The estimated 2,000 species of sea stars do not have a vertebrae like fish and therefore are not fish. Sea stars have two sides: dorsal, or top, and ventral, or bottom. Each side provides certain functions for the creature to exist.

Mouth
- The mouth of the sea star is located in the center of the ventral side. Sea stars possess the ability to push the lower section of their stomach out through the mouth. This enables the creature to consume larger prey, such as clams, mussels and oysters. The sea star first opens the shell and then the stomach takes in the food source directly rather than relying on the mouth.
Tube Feet
- Sea stars depend on hundreds of tube feet located on the ventral side for movement. The tube feet move the sea star by means of suction. One part of the body attaches to the surface as another releases allowing the sea star to move like a wave. The suction force is the result of water entering the tube feet from the water vascular system.
Water Vascular System
- The water vascular system circulates saltwater throughout the sea star's body. Besides providing suction for the tube feet, the system uses force to open the shells of clams and mussels. This system uses cilia, or projections resembling hairs, and ampullae, or structures, to keep the water circulating.
Radial Symmetry
- The ventral view shows the "arms" of the starfish, which exhibit a radial symmetry as they stretch out from the center of the species. The arms contain the tube feet. Starfish have the ability to regenerate an arm, and in some species one arm can regenerate into a new starfish. Most species have five arms but some have as many as 11 arms.

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