sea urchin

Description:

small, spiny, globular animals that, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum.

Habitat:

Sea urchins can be found all over the world in all oceans, warm or cold water. They live in a variety of environments in many different parts of the world. Some common places they live are in rock pools and mud, on wave-exposed rocks, on coral reefs in kelp forests and in sea grass beds.