Annals of the South African Museum, Volume 7

adult African angle anterior apertures appears atherstoni baini Band becomes beds bone border Broom characters closely collection comparable comparison considerably convex Cretaceous curved d'Orbigny described developed diameter differs direction distinct distinguished dorsal doubt elongated evidence fauna figure flank fossils front frontal further genus Geol greater greatest half height Holcostephanus individual Jurassic known lateral length less lower margin marked measures middle Museum narrow Neocomian obtained occur Oomia ornamentation outline passes Plate portion posterior present preserved probably prominent referred regarded region relatively remarks represented resemblance ribs ridges Rogers rounded sculpture seems seen separated Sharpe shell shown shows side similar single slightly South African species specimen stage Sunday's River surface Tate traced Trigonia tubercles Uitenhage umbilical umbo umbonal upper valve whorl