OBSERVATIONS ON THE GENUS UNION

Together With Descriptions of New Genera and Species in the Families Naiades, Conchæ, Colimacea, Lymnæana, Melaniana and Peristomiana, Consisting of Four Memoirs Read Before the American Philosophical Society From 1827 to 1834Description of Six New Species of the Genus Unio, embracing the Anatomy of the Ovi duct of one of them, together with some Anatomical Observations on the Genus.Description of a New Genus of the Family of Naiades, including Eight Species, Four of which are New, also the Description of Eleven New Species of the Genus Unio from the Rivers of the United States