Introductory material

Note. The references in the footnotes require a word of explanation. The titles of the works referred to will be found in the Bibliography at the end of the volume. In this list the authors’ names are arranged alphabetically and the papers of each author are in chronological order. The numbers in brackets after the author’s name in the footnotes, and before his name in the bibliographical list, refer to the year of publication. Except in cases where the works were published prior to 1800, the first two figures are omitted: thus Ward (84) refers to a paper published by L. F. Ward in 1884. This system was suggested by Dr H. H. Field in the Biologisches Centralblatt, vol. XIII. 1893, p. 753. (Ueber die Art der Abfassung naturwissenschaftlicher Litteraturverzeichnisse.)

PART I. GENERAL.