Members of the family Echinidae are characterized by having trigeminate ambulacra (quadrigeminate in one genus) with pairs of tube feet pores arranged either as vertical arcs or as a dense band. The ambulacral plates are compound. The tubercles are imperforate and do not have crenulate edges. There are few tubercles on the interambulacral plates. The buccal notches are reduced in size and, their most significant distinguishing feature, the pedicellariae are globiferous and have one or two pairs of lateral teeth on the narrow tubular blades.