1904. Die xerophilen Enchytraeiden der Schweiz. Biol, Centralbl., Bd. XXIV, pp. 501-513. Quantitative studies of earthworms in the soil. BRUNNER, J. 1912. Tracks and Tracking, pp. 219. New York. Outing Publishing Co. An illustrated guide for the identification of mammal and bird tracks or foot prints. Devoted mainly to game and fur-bearing animals. Very valuable to the student of live animals in nature. Many of our smaller species are worthy of similar treatment. BURNS, F. L. 1901. A Sectional Bird Census. Wilson Bulletin, N. S., Vol. VIII, pp. 84-103. A quantitative study of the birds found breeding on an area of one square mile. Other similar studies should be made. CHAPMAN, F. M. 1900. Bird Studies with a Camera. With Introductory Chapters on the Outfit and Methods of the Bird Photographer, pp. 218. New York. The title clearly indicates the character of this book. COMSTOCK, J. H. 1897. Insect Life. pp. 349. New York. Directions for the study of insects. CLEMENTS, F. E. 1905. Research Methods in Ecology. pp. 334. Lincoln, Nebraska. Important for methods of study in plant ecology, partly also applicable to animals; photography, and instruments for the study of environments. DAHL, F. 1901. Was ist ein Experiment, was Statistik in der Ethologie? Biol. Centralbl., Bd. XXI, pp. 675-681. 1903. Winke für ein wissenschaftlicher Sammeln von Thieren. Sitzungs-Ber. der Gesell. naturfor. Freunde zu Berlin. Jahrg. 1903, pp. 444-475. This contains, in addition to its suggestions on collecting, an interesting outline or classification of animal habitats (Cf. also Enderlein, 1908, pp. 72-77). This is not a genetic classification. Dahl’s list of habitats will prove very suggestive to the student who wishes to develop the genetic system of classification. Ultimately we must, of course, develop the latter system. 1904. Kurze Anleitung zum wissenschaftlichen Sammeln und zum Conservieren von Thieren. pp. 59. Jena. An enlarged edition of the preceding paper. DAVENPORT, C. B. 1904. Statistical Variation with Special Reference to Biological Variation. Second, Revised Edition. pp. 223. New York. FORBES, S. A. 1907. An Ornithological Cross-Section of Illinois in Autumn. Bull. Ill. State Lab. Nat. His., Vol. VII, pp. 305-335. 1908. The Mid-Summer Bird Life of Illinois: A Statistical Study. Amer. Nat., Vol. XLII, pp. 505-519. FLAHAULT, C., and SCHRÖTER, C. 1910. Phytogeographical Nomenclature. Reports and Propositions, IIIᵉ Cong. Inter. de Bot. 1910. Bruxelles. pp. 28. Zurich. A very valuable discussion of ecological nomenclature for plants. Defines the use of such terms as biology, ecology, habitat, association, formation, etc. It is very desirable that the plant and animal ecologists coöperate as much as possible in this subject. GIBSON, W. H. 1905. Camp Life in the Woods and the Tricks of Trapping and Trap Making. pp. 300. New York. A book for boys, but not without value to the older student of live animals. HENSEN, V.