sea urchin

Sea urchins are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone — from the intertidal seashore down to 5,000 metres. The spherical, hard shells of sea urchins are round and spiny, ranging in diameter from 3 to 10 cm Sea urchins are also a great delicacy in Japanese cuisine, where they are known as 'uni', and often used in sushi, or served sashimi-style. ... The sea urchin gonads can be cooked and are sometimes puréed into a velvety-rich sauce but they are most often served raw. It's not very easy to get hold of sea urchins.