Caitlin's+Starfish

=Exploring Caitlin's Starfish (Sea Star)= //Patriella regularis//
 * Common Cushion Starfish**

Their nervous system is spread through their arms and their “blood” is actually filtered sea water.
Top view
 * [[image:P1190214.JPG]]

Caitlin's Sea Star is a Common Cushion starfish. Starfish are called //kiri taratara// in Maori It has 5 arms but some starfish have 10, 20 and even 40 arms! || Bottom view Sea Stars are famous for their ability to grow new limbs and in some cases, entire bodies. This is because most or all of their vital organs in their arms. || The mouth is on the underside. It can eat outside its body! It oozes its stomach inside a shell, digests the snail, then slurps its stomach back inside. A stomach like this very useful if the Sea Star wants to eat something bigger than its mouth. || The photoreceptor eyespot at the end of each arm. It 'sees' only light and dark - still useful if a predator, lurking close, by casts a shadow. ||
 * [[image:starfish_and_damsel-54.jpg align="center"]]
 * [[image:starfish_and_damsel-55.jpg align="center"]]

Little pincers on moveable stalks pick up sand and dirt. This keeps the surface clean and stops other organisms growing on the Sea Star. You can also just see the hard calcite plates (the rounded orange-coloured bits), which are joined together to form the Sea Stars body. ||

The Sea Star looks to be covered in jewels - sapphires, diamonds and rosy quartz! Actually they are ossicles and pustules, making coloured patterns to camouflage the Sea Star, or warn predators away. ||
 * [[image:starfish_and_damsel-57.jpg align="center"]]

These little holes are found all over the top of the Sea Star. They behave like little drain holes, allowing water to enter the Sea Star. ||

A close-up of a Sea Star spine. The spines are hard, to protect the sea star from predators. Can you see the hinge at the base? It allows the spine to bend without breaking. Spines like these are found as fossils in ancient sea floors. ||
 * [[image:starfish_and_damsel-53.jpg align="center"]]

These little canals house the Sea Star's sucking, tube feet. Its feet are soft with little suction cups at the end to help it grab a surface. Along the edge of the canal are lots of spines that help to protect the feet. ||

This looks like a tiny sieve - and it is! Its called a //madreporite// and filters water into the sea star. The Sea Star uses water like tiny hydraulic jacks all through it, to bend and twist its body as well as to make the ripple-like movements of its feet when the Sea Star travels along. ||