Wikipedia
Spatangidae
The Spatangidae are a family of heart urchins. There are four recognised genera within the family; Maretia, Paramaretia, Pseudomaretia and Spatangus. Additionally, Spatagus and Prospatangus were previously recognised genera within the Spatangidae, but are now accepted as part of the genus Spatangus.
The Spatangidae are marine heart urchins that feed on subsurface deposits and graze.