In 1878 Tenison-Woods described under the name Echinanthus tumidus an echinoid which was housed in the Australian Museum and which was believed to have come from the coast of New South Wales. The specimen was damaged in the region of the actinostome and the test was almost devoid of spines. Holes had been bored through the actinal surface, possibly with a view to mounting the specimen on a board. Bell (1884, plates 11 and Ill) amplified Tenison-Woods's brief description and erected a new genus, Anomalanthus, to accommodate the species. Subsequently, Mortensen (1948) placed the species in the genus Clypeaster but added little to knowledge of the species.