1. Echinoderms
Aquatic Animals
)Zoo-521)
Jawaher Al-Zahrani

2. Order: Clypeasteroide
Scientific Classification
Kingdom: Animalia
Phylum: Echinodermata
Subphylum: Asterozoa
Class: Asteroidea
Class: Holothuroidea
Class: Echinoidea
Order: Clypeasteroide

3. Star Fish
1-Sea star or star fish are characterized by radial symmetry, several arms (5 or multiplied by 5) radiating from a central body.
2-Mouth on the underside , the anus is at the center of the disc together with the water intake (madreporite) on the top.
3- The upper surface is often very colorful.
There are cilia like structures that ensure that the surface of the arms stay free from algae.

6. Sea cucumber
1-They do not have distinct radial symmetry but are bilateral with a distinct dorsal and ventral part.
2-They have a leathery , elongated, muscular , flexible body with a mouth at one end the anus at the other end.
3-Around the mouth there is a number of tentacles (modified tube feet) used in food collecting.

9. Sand dollar
1-The sand dollar is a spiny , hard-skinned animal that is shaped like a coin.
2-Sand dollars have 5-part radial symmetry.
3-It has a hard skin made of calcium carbonate plates.
4-The bottom surface contains the mouth, many black spines
(which trap food), and the cilia (small) hairs that help direct food into the mouth.
5- Sand Dollars have tiny tube feet that are used as gills.
6- The holes on the top surface are where the eggs and sperm are released.