THE first edition of Prof. Arldt's great work appeared in 1907. Since that time, great advances have been made in palseogeography, bio-geography and related sciences. Further, a complete new theory of the origin of continents and oceans has burst upon the geological world. This second edition is therefore a greatly expanded one, the first volume of it alone amounting to a thousand pages. The first part of this volume, issued in 1936, was noticed in NATURE of May 29, 1937, pp. 902-3. In it the question of the permanence of the earth's major features was raised, and the answer is not yet forthcoming even in the thousand pages of the present volume. It seems likely, however, that land-connexions between continental masses will be approved, but for the final answer we must await the second volume, which will contain the geological and cos-mological findings.
Die Entwicklung der Kontinente und ihrer Lebewelt
Ein Beitrag zur vergleichenden Erdgeschichte. Von Prof. Dr. Theodor Arldt. Zweite, vollständig neu-bearbeitete und erweiterte Auflage. Band 1. Pp. xviii + 449–1005. (Berlin: Gebrüder Borntraeger, 1938.) 44 gold marks.