asterias forreri, use these spines to grab objects. The lower surface of the sea star has five or more radial grooves, one for each arm, beginning at the central mouth. These grooves protect the hundreds or thousands of pedicellaria - the tubular feet appendages which are flexible and have a sucker at the tip, allowing the starfish to crawl and to hold on to items such as bivalves, a food source, to open them. They also help push food into the mouth (Shine, 2002). The mouth in the center of the underside, surrounded by a series of moveable spines which act like a grating to prevent food from falling out of the mouth, and on the upper side, the anus (Boyer and Bearzi, 2003; Shine, 2002). Rudimentary eyespots can be seen on the upper surfaces of the tips of the arms, and these can detect changes in light.
The internal body structure of sea stars is simple and consists of skeletal plates within each arm which are not fused, giving the body great flexibility (Shine, 2002). The digestive system consists of an esophagus, stomach, and short intestinal tract. The nervous system c
...