. Annual report. New York State Museum; Science; Science. Pteronitella hirundu downward and back; right valve flat except at the beak. Surface of left valve bearing sharp and numerous radial lines, crowded and with a tendency to fasciculation over the anterior and lower parts but equidistant posteriorly. The hinge and ligament areas are bounded and crossed by a few very strong striae, the cardinal edge of the valve being thickened. All these lines are crossed by con- centric striae, short and elevated everywhere except on the posterior cardinal surface. On the right valve the radial lines are
. Annual report. New York State Museum; Science; Science. Pteronitella hirundu downward and back; right valve flat except at the beak. Surface of left valve bearing sharp and numerous radial lines, crowded and with a tendency to fasciculation over the anterior and lower parts but equidistant posteriorly. The hinge and ligament areas are bounded and crossed by a few very strong striae, the cardinal edge of the valve being thickened. All these lines are crossed by con- centric striae, short and elevated everywhere except on the posterior cardinal surface. On the right valve the radial lines are obsolete. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original New York State Museum. Albany : University of the State of New York
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectscience, bookyear1902
