There are four basic styles of lantern found in regular echinoids, varying in the depth of the foramen magnum, the cross-section of the tooth and the development of the epiphyses. Lantern segments of each type seen in external view are illustrated above, and in internal view below.
Cidaroid. The lantern is narrow and with only a tiny foramen magnum. Epiphyses are small and do not project and the teeth are U-shaped in cross-section. Characteristic of all cidaroids.
Aulodont. The lantern has a deep-V-shaped foramen magnum and epiphyses tend to have small finger-like projections which are free. Teeth are U-shaped in cross-section. Characteristic of echinothurioids, diadematoids and pedinoids.
Stirodont. Basically as in aulodont, but with teeth T-shaped in cross-section. Characteristic of arbacioids, salenioids and stomopneustids among others.
Camarodont. There is a deep V-shaped foramen magnum and epiphyses are enlarged and meet above the foramen magnum forming a continuous arc. Teeth are T-shaped in cross section. Characteristic of the orders Temnopleuroida and Echinoida.