Starfish: A representative class of echinoderms. Most of them are five-radiation symmetry, and the boundary between the body disk and the wrist is not obvious. The endoskeletal bone plate is mainly connective tissue, flexible and bendable. There are spines and forked spines on the body surface, and the bones are prominent. Vesicular process of membrane. The water pipe system is relatively developed. There are two growth processes: feather wrist larva and short wrist larva.

The radial diameter is about 1-65 cm, mostly about 20-30 cm, and it is covered by short thorns and forked thorns. There are pipe legs in the ditch, so you can crawl in any direction, even on steep surfaces. Higher types of stomach can be swallowed whole. The endoskeleton is mainly composed of calcareous bone plates, which breathe through the skin. Most of them are hermaphroditic, and a few are hermaphroditic; Some can divide asexually. There are 0/600 species of starfish/kloc-and about 300 species of fossils, which are distributed in sandy and soft mud seabed.

Starfish and sea cucumbers are echinoderms. There are five wrists and four or six wrists, mostly star-shaped. Calcareous bone plate is composed of connective tissue, and there are spinous processes and warts on the body surface. Some reach 50, and there are 4 rows of pins on the lower side. It can not only catch prey, but also climb rocks. The big one has thousands of pins. The mouth is located in the middle of the lower side of the body and is in contact with the surface that the starfish has climbed. Different sizes, small 2? About 5 cm, about 90 cm, and the body color is different. Almost every kind is different, including red, purple and cyan. ?

Some species have short wrists and pentagonal bodies, such as bread starfish. The central area from the wrist to the center is scientifically called the walking area, also known as the radiation area. The interval between steps is called intermediate step area, also called intermediate radiation area. Starfish are carnivores and feed on invertebrates, especially shellfish, crustaceans, polychaetes and fish. Some monogamy, such as animals that only eat bivalves. Starfish also have omnivorous and omnivorous species.

Feeding method: when feeding, the body is on the shell and the wrists are sucked on both sides. The sucker at the end of the tube foot opens the mouth of the shell, the starfish comes out of the spout, the stomach is inserted into the mouth of the shell, digestive enzymes are secreted until digestion, and the shell is opened to surround the food in the mouth.