Moreover, all our knowledge of organic remains teaches us, that species have a definite existence, and a centralization in geological time as well as in geographical space, and that no species is repeated in time.

In the autumn of the same year he registered at Edinburgh as a student of literature; and in 1838 appeared his first volume Malacologia Monensis a synopsis of the species of Manx Mollusca. The year 1851 witnessed the removal of the collections of the Geological Survey from Craig's Court to the museum in Jermyn Street and the appointment of Forbes as professor of natural history to the Royal School of Mines just establiEdward Forbesd in conjunction therewith. M.