Only a few animals belonging to the more important phyla, as viewed from an evolutionary standpoint, are considered. They are, however, intensively studied in an endeavor to teach the fundamental principles of Zoölogy in a way that is not possible when a superficial examination of types from all the phyla is made. Furthermore, morphology is not specially emphasized, but is coördinated with physiology, ecology, and behavior, and serves to illustrate by a comparative study the probable course of evolution. The animals are not treated as inert objects for dissection, but as living organisms whose activities are of fundamental importance. No arguments are necessary to justify the “type course,” developed with the problems of organic evolution in mind, and dealing with dynamic as well as static phenomena. “I have read your chapter (The Crayfish and Arthropods in General) and can express my satisfaction with reference to the general arrangement of the matter, as well as with reference to the detail. The whole treatment is up to date, taking account of the modern advancement in our knowledge of the crayfishes, and, chief of all, the more important features in the natural history of these animals are very properly separated from the unimportant ones. I think this chapter gives the essence of what we know about crayfishes, and any student might use the book advantageously. In fact, I know no other text-book which gives such a wealth of information upon so few pages.”--Professor A. E. ORTHMANN, Carnegie Museum. “The plan is very satisfactory, and the book will be very instructive for class use. I am very glad that you have chosen the bee as your insect type.” (Chapter XII.)--Dr. E. E. PHILLIPS, Department of Agriculture, Washington, D.C. THE MACMILLAN COMPANY =Publishers= =64-66 Fifth Avenue= =New York= Household Bacteriology BY ESTELLE D. BUCHANAN, M.S. Recently Assistant Professor of Botany, Iowa State College AND ROBERT EARLE BUCHANAN, PH.D. Professor of Bacteriology, Iowa State College, and Bacteriologist of the Iowa Agricultural Experiment Station _Cloth, 8vo, xv + 536 pp., index, $2.25 net_