The Echinoid Directory

Key to subfamilies of Hemicidaridae

1a. Ambulacra composed entirely of simple elements above the ambitus. Spines clavate to glandiform.
Pseudocidarinae
1b. Ambulacra remain basically trigeminate to apex with small but distinct primary tubercle overlapping at least two of the three elements in each triad. Spines cylindrical, sometimes with distal crown.
Hemicidarinae