Sending his "Monography of the genus Callitriche" in addition to the "Description of a new species of Echeneis" sent with his last letter. Asks to be informed of recent botanical and zoological developments in England and Europe, including the publications of [Christiaan Hendrik] Persoon and [Carl Ludwig] Willdenow, "Hortus Kewensis", and Smith's "Flora Britannica" and "Flora Graeca". Details of his own intended publications "General generic criticism; or alphabetical criticism of all the generic names of botany & zoology" and "Order of plants". Impossibility of publishing in Sicily.