| A | B |
|---|
| habitat | all over the world in coastal waters and along rocky shores |
| food | oysters, clams |
| oral surface | the underside of its body where the mouth is |
| aboral surface | the top side of its body |
| endoskeleton | a skeleton found within the body |
| ossicles | calcium plates covered with a thin layer of epidermus which also form the spines on the aboral surface |
| pedicellariae | groups of tiny pincer like cells which help protect and clean the surface of the body |
| water-vascular system | a network of canals in which muscular contractions create hydrostatic pressure which permits movement |
| sieve plate | a small opening on the aboral side where water enters |
| madreporite | a calcereous pore beneath the sieve plate used for intake of water |
| stone canal | a water passage connecting the madreporite to the ring canal |
| ring canal | a water passage encircling the mouth and braching out to each radial canal |
| radial canal | water passage that extends from the ring canal to the hundreds of paired tube feet |
| ampulla | a bulblike sac at the upper end of each tube foot |
| suction | created and released by the contraction of the tube feet and the ampula which enbales the sea star to move, and to catch and open prey |
| stomach | gets turned inside out and is inserted into the bivalve |
| enzymes | secreted by the stomach to digest the bivalve while it is still in its shell |
| coelom | fluid in this body cavity bahtes the organs and distributes nutrients and oxygen |
| skin gills | holow tubes that project from the coelom lining |
| diffusion | method of gas exchange and waste excretion; through the thin walls of the tube feet and the skin gills |
| nerve ring | surrounds the mouth and branches off into nerve cords that extend into each arm |
| eyespot | found on each arm and is sensitive to light |
| tentacle (and tube feet) | found on each arm and is sensitive to touch |
| gonads | two in each arm, producing eggs in females and sperm in males |
| 200 million | eggs produced by one female in one season |
| bipinnaria | free swimming, bilateral larva from a fertilized egg |
| asexual reproduction | regeneration of lost parts |
| can still regenerate | a segment of an arm with intact portions of the central disc |
