. Bulletin - United States National Museum. Science. COSCINIUM PRiENUNTIUM, new species. Plate 7, figs. 5, 6; text fig. 69. Zoarium a bifoliate, flabellate, cribrose frond, 30 or raore ram. high and the same width, growing from an expanded base attached to foreign bodies. The individual branches are 2 mm. in width and 1 mm. thick. An average fenestrule is broadly oval in outline and is 2 mm. long and mm. wide. Base of zoarium and margins of branches noncellu- Hferous and finely granulose. Apertures subpyriform to trilo- bate in outhne with a distinct lunarium oc- cupying the posterior thir
. Bulletin - United States National Museum. Science. COSCINIUM PRiENUNTIUM, new species. Plate 7, figs. 5, 6; text fig. 69. Zoarium a bifoliate, flabellate, cribrose frond, 30 or raore ram. high and the same width, growing from an expanded base attached to foreign bodies. The individual branches are 2 mm. in width and 1 mm. thick. An average fenestrule is broadly oval in outline and is 2 mm. long and mm. wide. Base of zoarium and margins of branches noncellu- Hferous and finely granulose. Apertures subpyriform to trilo- bate in outhne with a distinct lunarium oc- cupying the posterior third or fourth. An average zooecium is mm. long; five in 2 mm., measuring lengthwise. Inter- zooecial spaces as wide and often wider than the zooecia, solid at the surface, granulose or granulostriate. Coscinium prsenuntium has a smaller zoarium than the later representatives of the genus. It differs too decidedly from other Ordovician forms to require comparison. Occurrence.—Rare in the Orthoceras Hmestone (B3), island of Rogo, Esthonia. Holotype.—Cat. No. 57243, Specimen and thin sections in the British Museum. Family ARTHROSTYLID^ Ulrich. Zoarium articulated, consisting of numerous subcylindrical seg- ments, united into small pinnate or bushy colonies, or of continuous, dichotomously divided branches; zooecia sub tubular, more or less oblique, radially arranged about a central axis, and opening on all sides of the segments; or one side may be noncelluliferous and longi- tudinally striated. Both the zooecial and zoarial characters of the Arthrostylidse are so distinctive that thin sections are seldom necessary for accurate specific determination. It is surprising that of the 12 species of the family identified in Russian strata, 10 are characteristic American forms. Fig. 69.—Coscenium PE^NimTroM. a, tangential section, X20; 6, VEBTICAL section, X20. OETHOCERAS LIMESTONE (B3), ISLAND OF RoGO, Please note that these images are extracted from scanned
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