What is the genus species name of a sea urchin?

Based on: http://en.wikipedia.org/wiki/Sea_urchin

... Sea Urchins are small, spiny sea creatures of the class Echinoidea found in oceans all over the world. ...

... Sea urchins are members of the phylum Echinodermata, which also includes starfish, sea cucumbers, brittle stars, and crinoids. Like other echinoderms they have fivefold symmetry (called pentamerism) and move by means of hundreds of tiny, transparent, adhesive "tube feet". ...

... Within the echinoderms, sea urchins are classified as echinoids (class Echinoidea). Specifically, the term "sea urchin" refers to the "regular echinoids," which are symmetrical and globular. The ordinary phrase "sea urchin" actually includes several different taxonomic groups: the Echinoida and the Cidaroida or "slate-pencil urchins", which have very thick, blunt spines (see image at right), and others (see taxonomic box on the right). Besides sea urchins, the Echinoidea also includes three groups of "irregular" echinoids: flattened sand dollars, sea biscuits, and heart urchins. ...

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