April 26th; Descriptions of Eight New Species of Unionidæ, from Georgia, Mississippi, and Texas; Ichthyological Notices; On the Primary Divisions of the Salamandridæ, with Descriptions of Two New Species; On the Genus Callionymus of Authors; Description of Hyporhamphus, a New Genus of Fishes Allied to Hemirhamphus, Cuv.; On Dactylosc and Leptoscopus, Two New Gunera of the Family of Uranoscopidae; Catalogue of Birds Collected on the Rivers Camma and Ogobai, Western Africa, by Mr. P. B. Duchaillu, in 1858, with Notes and Descriptions of New Species; Notes on a Collection of Japanese Fishes, Made by Dr. J. Morrow