†Hardouinia mortonis emmonsi Stephenson 1927 (sea urchin)
Alternative combination: Cassidulus emmonsi
Synonyms: Cassidulus berryi Clark and Twitchell 1915, Hardouinia stetsoni Stephenson 1936
Belongs to Hardouinia mortonis according to C. W. Cooke 1953
See also Clark and Twitchell 1915
Sister taxa: none
Ecology: slow-moving semi-infaunal detritivore
Distribution:
• Cretaceous of North Atlantic (1 collection), United States (4: North Carolina)
Total: 5 collections each including a single occurrence