THIS new volume of the International Scientific Series gives an excellent summary of the most recent researches as to the varied uses of the colours of animals, and more especially of those admirable observations and experiments on variable protective colouring with which Mr. Poulton's name is associated, and which mark an era in this branch of natural history. The main outlines of the subject are so well known, both to naturalists and to general readers, that it will only be necessary here to indicate some of the more important of the matters now first treated in a popular work, and to make a few remarks on some of the more difficult problems discussed in the volume. The Colours of Animals: their Meaning and Use especially considered in the case of Insects. By Edward Bagnall Poulton, &c. With Chromolithograph Frontispiece and Sixty-six Figures in Text. (London: Kegan Paul, Trench, Trubner, and Co., Limited, 1890.)