Easily distinguished from other toxopneustids by its subhorizontal arcs of pore-pairs some 6 or 7 to a plate. Biochemical work has shown that this taxon is closer to strongylocentrotids (N. Matsuoka 1987 Zoological Science 4, 339-347) and its ambulacral structure suggests sister group relationships with Hemicentrotus which differs in having rather less pronounced buccal notches without the tags.
Mortensen, T. 1903. The Danish Ingolf-Expedition 1895-1896. Vol. 4, No. 2. Echinoidea, pt. 1.Copenhagen, 198 pp.
Mortensen, T. (1943) A monograph of the Echinoidea Part III.2, Camarodonta 1. C. A. Reitzel, Copenhagen