NEW GENERA OF MIDDLE PALEOZOIC BRACHIOPODS

Eight new genera are proposed, three of them belonging to the Dal- manellacea and five to the Rhynchonellacea. The German Devonian genus Kayser- ella is revised and its interior figured and described. The German Devonian genus Mystrophora is described in detail and compared with Kayserella. The revision of Kayserella led to the recognition of a new German Devonian genus Phragmophora and a new French Devonian genus Monelasmina. The former belongs to the Onniel- lidae but the latter has the structure of the Schizophoriidae. A third new genus, Hypsomyonia, from the Upper Devonian of Iowa has a peculiar elevated adductor platform in the brachial valve. All these genera are interesting examples of homeo- morphy. In revising the Silurian rhynchonellid genus Stegerhynchus Foerste it was dis- covered that the name included more than one genus. Stegerhynchus was fixed by Schuchert on S. whitii (Hall) but Foerste's varieties from the Silurian at Clifton, Tennessee, appear to belong to the Russian genus Ferganella. The Lower Devonian rhynchonellid Rhynchonella formosa Hall is here described as Machaeraria, a new genus. Four other genera of rhynchonellid brachiopods are described as new: Fenestrirostra from the Silurian of Anticosti; Pegmarhynchia from the Lower Devonian of New York; Hyborhynchella from the Upper Devonian (Sly Gap) of New Mexico; and Porostictia from the Upper Devonian (Percha) of New Mexico.