LII.—On “Orthoceras [Endoceras] duplex,” Wahlenberg et auctt., with descriptions of three new species of Endoceras from the Ordovician of Sweden and Russia contained in the British Museum (Natural History)

(1887). LII.—On “Orthoceras [Endoceras] duplex,” Wahlenberg et auctt., with descriptions of three new species of Endoceras from the Ordovician of Sweden and Russia contained in the British Museum (Natural History) . Annals and Magazine of Natural History: Vol. 20, No. 120, pp. 393-402.