The name given by G. Cuvier in 1817 to an assemblage of echinoids in which the anus and periproct lie within the apical system. The test is globular and preponderantly radially symmetrical, and the ambulacral plates are commonly compound. The group included, in effect, all those echinoids which did not fall in the Irregularia. The Irregularia, however, were shown to be polyphyletic by J. Durham and R. Melville in 1957, and so neither the Irregularia nor the Regularia constitute valid taxa.