Sea urchins are spherical, hemispherical, heart-shaped or disc-shaped, and the colors are green, olive, brown, purple and black. Sea urchins are warm benthic species, living in reef forests or cracks in the sea below the intertidal zone rich in algae, and in hard and muddy shallow waters. Lurking in the mud during the day, coming out at night, crawling on the seabed with feet and thorns for food, and grinding food with a chew. The main food is seaweed, sponge and hydra.

The internal organs are contained in 1 shell, which is composed of many calcareous bone plates that are tightly healed. The shell is covered with many movable thorns. Each pair of pin holes on the shell plate is equivalent to 1 pin, and multiple rows of Hyderabad landscape are 10. The mouth is below, and there are five white teeth in the center, which are part of the chewing organ-Aristotle's lantern. 1 sea urchin shells are made up of about 3000 small plates.