(1) Therefore, the possession of the anterior, unpaired lunule in ambulacrum III, is a plesiomorphic character for the Mellitidae in general.(2) This type of lunule is completely unknown in any other echinoid.(3) Other measurements of test length, lunule lengths, widths, positions, apex position, and petaloid lengths were made from both the fossil and extant Leodia material using dial calipers.(4) This morphology most closely resembles A. (T.) rollandi Bernardi, 1859, but differs from it in having a thinner shell, less pronounced hinge area, and better-developed lunule .(5) A small median plate lying between the ptilinal fissure and the bases of the antennae is named the lunule .(6) The frontal lunule is a small crescent shaped piece immediately above the antennae, which is characteristic of the second suborder, the Cyclor rhapha.
