MellitidaeMellitidae is a family of sand dollars, in the echinoderm order Clypeasteroida. These irregular sea urchins bury themselves in soft sediment in shallow seas.GeneraThe World Register of Marine Species includes the following genera in the family:-Encope L. Agassiz, 1840Lanthonia Coppard, 2016Leodia Gray, 1851Mellita L. Agassiz, 1841Mellitella Duncan, 1889