NEW AMERICAN PALEOZOIC OSTRACODA. PRELIMINARY REVISION OF THE BEYRICIIIIDJE, WITH DESCRIPTIONS OF NEW GENERA/' By Edward 0. Uleich, Geologist, U. 8. Geological Survey, AND Ray S. Bassler, Curator, Division of Invertebrate Paleontology. INTRODUCTION. As defined in modern text-books, the Paleozoic family of Ostra-coda, Beyrichiiclay embraces a large and constantly growing assem-blage of genera and species. The unwieldiness of the typical genus Beyrichia became apparent some forty years ago, when T. Rupert Jones, the well-known and highly conservative English authority. and H. B. Holl tirst suggested the separation of the " siniplices " as a distinct generic group under the name Primitia? At a later date these authors proposed the separation of the less sharply defined " Corrugatse " group, typified by Beyrichia wilckensiana, under the name Klmdenia. In the same paper they propose the genus Bolliaf and in the next succeeding number of that periodical two other generic groups are distinguished as Strepula ' and PlacentulaJ Working independently, Jones had also instituted the genus Kirk-bya.o for a Permian species thought to have relations to the Bey-" For previous articles of this series see Jour. Cincinnati Soc. Nat. Hist., XIX, 1900, pp. 179-185, and Proc. U. S. Nat. Mus., XXX, No. 1446, 1906, pp. 149-164, pi. xi. » Ann. and Mag. Nat. Hist. (3), XVI, 1865, p. 415. In 1855 (Ann. and Mag. Nat. Hist. (2), XVI, p. 85), Jones divided Bey-richia, as then defined by him, into three groups, (1 ) " siniplices," including the forms subsequently referred to Primitia and allied genera; (2) "Corrugatse," with li. tcilekensiana as the type of the group, and (.'!) " Jugosse," including, besides /»'. kloedeni, the type of the genus, also certain Ordovician species subse-quently referred to Tetradella and Ctenobolbina by Ulrich. 'Ann. and Mag. Nat. Hist. (5), XVII, pp. 347, 362. d Idem, p. 300. ( ' Idem, p. 403. ' Idem, p. 407. t> Trans. Tyneside Nat. Field Club, IV, 1859, pp. 129, 134, 136. Proceedings U. S. National Museum, Vol. XXXV— No. 1 646. 277
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