IN his presidential address delivered last November to the Royal Irish Academy, Dr. R. Lloyd Praeger returned to a subject which has occupied his attention for forty years—the problem of the Irish flora and fauna (Proc. Roy. Irish Acad. 41, 125). The problem has been much discussed, but always with an obscurity of background due to absence of fossil evidence which might give the clue to the routes and periods of past immigrations. In such circumstances conclusions assume a personal interpretation and Dr. Praeger's view is that much of the present flora and fauna reached Ireland over land-surfaces, either during inter-glacial (Aurignacian) times, or in the same way after the ice had finally passed away, or probably during both periods. Certain plants and animals found with these immigrants, including the American and probably the Lusitanian element, are older than these, and survived the main glaciation. These oldest elements migrated northward in pre-glacial times along the western European coast line, or eastward from America when the intervening barriers of sea were at least much less formidable than they are at present.