- among the horizontal elements when you look at the centra associated with the vertebrae in certain fossil batrachians.
- among the horizontal elements in the centra of vertebræ in certain fossil batrachians.
- One of the horizontal components of the centrum of a vertebra; a hemicentrum.
- A dorsal aspect in the rachitomous vertebras of specific ganoid fishes and stegocephalian amphibians. Its homologous because of the centrum of this reptilian and mammalian vertebra.