What looks like eyes on sea urchins may be their anal papillae, whose main function is to excrete. Sea urchins have a special organ, they do not have eyes. Although they do not have eyes, they have similar organs to sense their surroundings. Sea urchins have some epidermal cells on their antipodal surfaces that have eye spots on them to sense the outside light. There are also more light-sensitive cells on their spines and on their peduncles, enough for them to move around. First, the sea urchin like eyes on what

sea urchin like eyes on the thing is the anal papillae, they are not eyes, but the sea urchin excretory holes, the sea urchin is through the anal papillae to discharge the body waste. Although the sea urchin has no eyes, but they have a lot of auxiliary organs to sense the external environment. For example, they have some epidermal cells on their antiproctal surface that help them sense the outside light. Also, there are a lot of photoreceptor cells on their spines and peduncles, which are enough for them to survive and move around. This means that the more spines on the sea urchin, the more sensitive they are to light.

Second, the sea urchin has legs

Sea urchins do not have legs, they are echinoderms, belonging to a relatively low-level animals. The structure of the sea urchin is relatively simple, they are round, there are a lot of spines on the shell, in addition, they have no other organs, so the sea urchin is no legs. Although they do not have legs, they can use the spines to change their position. As they move around, they slowly adjust the position of the spines so that they can roll up like a ball, so the spines can also be counted as the sea urchin's legs. Of course, the sea urchin's spines are still different from the legs of other animals; they don't allow the sea urchin to move quickly, only slowly.