Article: A new variety of Orthoretiolites hami Whittington

A variety of Orthoretiolites hami Whittington is recorded from two levels in the Viola limestone of Oklahoma. The varietal distinction is based on the more robust nature of the clathria and the presence of a structureless periderm. Early growth stages recovered illustrate the initial development of the species O. hami whilst adult stages are represented in several rhabdosomes. It is concluded that, in spite of its mode of development, the genus Orthoretiolites could be most conveniently placed in the family Retiolitidae.