. Annual report of the regents of the university of the state of New York on the condition of the State Cabinet of Natural History and the historical and antiquarian collection annexed thereto. another specimen, showing the closed rounded pseudo-• deltidium. ORTHISINA ALTERNATA(). Shell of medium size, semielliptical : hinge-line shorter than the greatest widthof the shell; cardinal extremities rounded. Ventral valve most gibbous near theumbo and depressed near the front : area moderate, somewhat arcuate; pseudo-deltidium large, broad at base, imperforate, marked along the middle by adeep
. Annual report of the regents of the university of the state of New York on the condition of the State Cabinet of Natural History and the historical and antiquarian collection annexed thereto. another specimen, showing the closed rounded pseudo-• deltidium. ORTHISINA ALTERNATA(). Shell of medium size, semielliptical : hinge-line shorter than the greatest widthof the shell; cardinal extremities rounded. Ventral valve most gibbous near theumbo and depressed near the front : area moderate, somewhat arcuate; pseudo-deltidium large, broad at base, imperforate, marked along the middle by adeeply impressed line. Dorsal valve regularly convex, apparently without sinus;area linear or obsolete. Surface marked by fine radiating striae, alternating insize, usually three smaller between the larger ones near the margin of the shell;distinctly undulating concentric striae. The margin of the shell is species differs from the last in the proportionally shorter hinge-line and the alternating larger and smaller striae, which are also less prominent and less closely arranged. Geological formation and locality. Shales of the Hamilton group : Genesee county, 1 2.
Size: 1891px × 1321px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1850, booksubjectscience, bookyear1853
