A huge family with more than twenty genera and 300 species. Formerly placed in the Choriplacidae, now a family on its own. Characteristics to see in the sculpture of the plates and the type of girdle characteristics. The latter is covered with imbricating scales. The family has a worldwide range.
For a list of genera and species:
http://www.marinespecies.org/aphia.php?p=taxdetails&id=69