Sea urchins are a type of marine life. Take stock of many different species.

Sea urchins are a group of marine organisms that come in many different species. Here are some common sea urchin species:

1. red sea urchin: Red Sea Urchin is a species of sea urchin widely distributed in all oceans around the world, with a red or orange appearance.

2. Purple sea urchin: Purple Sea Urchin is also a common sea urchin species with a purple shell. They usually live on the surface of rocks or coral reefs.

3. Short-Spined Sea Urchin: Short-spined sea urchins have relatively short spines and are usually found on ocean rocks. They can come in a variety of colors, such as red, orange, and purple.

4. Long-spined Sea Urchin: The spines of Long-Spined Sea Urchin are relatively long and appear in bright colors, such as red, blue and green. They usually inhabit rocky and coral reef areas.

5. White Sea Urchin: White Sea Urchin is a species of sea urchin with a white appearance that usually lives in tropical and subtropical waters.

6. horse dung sea urchin (Hemicentrotus): Horse dung sea urchin is brown, has short spines and looks like horse dung. They are mainly distributed in the Yellow Sea, Bohai Sea of China and Hokkaido, Japan.

7. Japanese Sea Urchin: Japanese Sea Urchin is a species of sea urchin that is particularly common in Japanese waters. They are widely used as sashimi in Japanese cuisine.

These are some common species of sea urchins, each differing in appearance and living habits. As a type of marine life, sea urchins have a wide range of species diversity, and there are other species not mentioned.