Introduces [John] Bradbury, who is returning to England after travelling up the Missouri river. Rafinesque asks for his papers to be returned if they are not being published in "Linnean Transactions". Requests introductions to [William Elford] Leach, [Robert] Brown, [Aylmer Bourke] Lambert, [Richard] Salisbury, and "other eminent botanists and zoologists". Criticises Pursh's "Flora America Septentrionalis" for copying names previously published himself. Dr [Samuel Latham] Mitchill of New York [(1764-1831) naturalist] has published 60 new species of fish in first volume of "Transactions of the [New York] Society" and presented them with account of reptiles, crustaceans, testaceurs etc. Rafinesque has discovered new additional species: 'Perca mucronata', 'Petromyzon xanthodon', 'Phycis marginatus', and presented memoir to New York Philosophical Society on Sturgeons of North America. Plans to explore Lakes Champlain and George, [Vermont and New York] for fish.