Psammechinus miliaris is a species of sea urchin in the family Parechinidae.

Calveriosoma gracile is a species of sea urchin in the order Echinothurioida.

Antrechinus drygalskii is a species of sea urchin of the family Urechinidae.

Arachnoides placenta is a species of sea urchin of the family Clypeasteridae.

Phormosoma placenta is a species of sea urchin in the order Echinothurioida.

Echinus tylodes is a species of sea urchin in the Echinidae family.

Eucidaris metularia is a primitive species of sea urchin and comes from an ancient lineage that has hardly changed over the past 150 million years.

Plesiocidaris durandi is an extinct species of sea urchin.

Aporocidaris antarctica is a species of sea urchin of the family Ctenocidaridae.

Diadema urchin can refer to several species of sea urchin.