of classification and of the relations and development of organic life on the globe would find a place. This task presented many difficulties, both for the revisers and for the editor, and one can not but regret that the cost of illustration and the difficulties of finding a publisher for a wholly new work stood in the way of preparing a manual which should be avowedly, as well as practically, independent. The excellent work of von Zittel, good as it is, was designed on the lines of the science as it was a quarter of a century ago. The revision, though in several departments fundamental, is naturally more or less uneven, the restrictions of space insisted on by the publishers and other causes hampering the freedom of treatment desirable, while the composite nature of the work, part of which was stereotyped before other portions were received in manuscript, has inevitably resulted in some incongruities. However, in spite of such minor deficiencies, the result has been the most notable advance in the treatment of invertebrate paleontology as a whole since text-books began to be made. This is especially evident in such groups as the Polyzoa, Mollusca, Brachiopods and Trilobites, in which the illustrations and a part of the bibliography are all that remain of the older work. Any work in which the latest views of large divisions of the animal kingdom are summed up by such experts as Wachsmuth, Ulrich, Schuchert, Hyatt and Beecher must appeal strongly to students and long remain an indispensable aid to science, whether all matters of detail meet with final acceptance or not. Wholesale changes, such as are indicated in several of the groups, might very well be unacceptable to the original author of the work thus modified, but, while suspending his opinion on the advisability of some of the novel methods, Dr. von Zittel, in his preface to the present work, has been moved by the true scientific spirit which, while holding fast to that believed to be good, is ever ready to welcome any new light. The untouched riches of American fossiliferous horizons, especially above the Paleozoic, are almost incalculable, and the existence of Dr. Eastman's valuable text-book can not but be a most important factor in the training of those who will hereafter bring to light the riches now awaiting the advent of paleontological explorers.
ZOOLOGY.
There has been somewhat of a dearth of works on natural history during the past few months. Among those which have appeared is 'Nature's Calendar,' by Ernest Ingersoll, a book intended to stimulate the reader's power of observation by inducing him to note down, day by day, what he sees going on in the world of animals and plants about him. There are twelve chapters, one for each month, in which the author writes pleasantly of what is being done by the more familiar beasts and birds, reptiles, fishes and insects, as well as plants, in an ordinary season in the vicinity of New York. The limits, however, have not been very rigidly drawn, and we read of deer, bears and wildcats, animals not commonly found about that city. We are told, as the case may be, how animals and plants are guarded against extremes of heat and cold, at what time the animals make their appearance, when the woodchuck comes from his burrow and the shad and herring ascend the streams; when they mate; at what time the eggs are deposited or the young come forth; at what time the buds burst and the blossoms open, and of many other occurrences. Each chapter is preceded by a full-page plate, after photographs by Clarence Lown, of some landscape in accord with the text, and at the end of each chapter is a 'calendar,' in which the birds naturally appear in the majority, stating what animals are present, the approximate times at which, if they migrate, they come or go, or the dates on which they go into or come out of winter quarters. The compact text oc-
