Article: The Ordovician trimerellid brachiopod Eodinobolus from south-east Ontario

Obolus canadensis Billings, Obolellina magnified Billings, and Dinobolus erectus Wilson are redescribed. The species are Wilderness (early Caradoc) in age. Rowell recently assigned all three species to Eodinobolus and chose Obolellina magnifica as the type species. The internal structures of the three species are described from silicified material. A hypothesis is presented for the mechanics of the opening and closing of the shell and requires articulation about a poorly defined hinge that is analogous in its position to that of the Class Articulata.