Distinguished from the rather similar Selenechinus by having more strongly developed secondary tubercles aborally and much less granulation. Also differs in having pore-pairs of the inner series forming a clearly separated column. Differs from Parechinus in having a primary tubercle to every second or third ambulacral plate.
A fossil taxon from Australia ascribed to this genus by Philip (1969) has the triserial pattern of pore-pairs only really expressed below the ambitus.
Philip, G. M. 1969. The Tertiary echinoids of south-eastern Australia IV. Camarodonta (2). Proceedings of the Royal Society of Victoria 82, 233-275, pls 3-16.
Verrill, A. H. 1871. Notes on Radiata. Transactions of the Connecticut Academy 1, p. 583.