Proceedings of The Academy of Natural Sciences, 1857

abdomen Acad Academy Acid albâ aluminium antennis anteriorly antice aperture apices Bad Lands basin beaks Bishop Elliott breadth brown Caput Cassin CEREBRATULUS Clivina collection color convex Corpus Cretaceous dentibus cardinalibus deposits Description distinct dorsal ellipticâ elytra ENTELODON Eocene epidermide feet formations fossils frenal frontal Gaboon genera genus Geological Gory head HELIX inches iridescente Isaac Lea Joseph Leidy labials lamellatis lateralibus LeConte Leidy length LEPTOPLANA lignite Lime lines Locality and position longitudinal margaritâ margin Miocene Missouri natibus prominulis Nebraska obliteratis Ocelli Oreodon Orthoptera peristome Phosphoric Acid Planaria plates poll posterior posteriorly postice Presented by Dr Proc Prof radiatâ remarkable rock rows sandstone scales scutes shell side skulls species specimens striæ striis supra supra-labials surface T. B. Wilson tail teeth Tentacula Tertiary Testâ lævi thorace tibiæ transverse umbilicus UNIO upper utrinque valde valdè inæquilaterali White River whorls yellow