of American ornithology is outlined and divided off into periods, from its beginning in the seventeenth century to the present time. The first edition of Professor Coues's "Key" appeared in 1872, in an issue which was not stereotyped, and has been long out of print. It was composed upon the same general plan, and with the design of reaching the same ends, as the present edition, but had an artificial key to assist in the reference of specimens directly to their genera, which has not been found useful enough to justify its retention. It answered its purpose well, of giving such descriptions of species as would enable the student to identify and label them with no other aid than itself afforded. It had a useful career till the issue was exhausted and no more copies could be had. During the twenty years that elapsed before the present edition was ready for the press, American ornithology had a great development. The number of distinguished species increased to nearly nine hundred; numerous treatises were published on the subject; a distinctly American school grew up, introducing important changes in nomenclature and classification; and an American Ornithologists' Union was founded, with members in all quarters of the globe. In preparing this edition, the classification and nomenclature have been modified to suit the growth of the science; the author's "Field Ornithology," published separately in 1874, has been incorporated in the volume; the outline of "Structure and Classification" has been greatly amplified; and the descriptions of genera, species, and sub-species have been made much more elaborate, without loss, the author hopes, of that sharpness of definition which was the aim of the first edition and still having prominently in view the main purpose of the identification of specimens. The trinomial nomenclature, for the designation of sub-species and varieties—which "lends itself so readily" to the nicest discriminations of geographical races and the finest shades of variation—has been employed with much advantage, but not without a caution by the author against a too free use of it. The references to authorities, which were numerous in the first edition, have been omitted, and their place filled with additional notes about the habits and nesting of the species. The present edition contains about four times as much matter as the former one, and more than double the number of illustrations. We are sorry to observe that the author has not, in his preliminary chapters, preserved the dignity of style that is becoming in scientific works, or in any serious work, but has allowed himself to indulge too often in sensational expressions and jokes that are not always new or refined, to the unnecessary expansion of the text, without adding to its lucidity or its interest. The fault is not so obvious in the descriptive part of the book.
Mental Evolution in Animals. By George John Romanes, F. R. S., author of "Animal Intelligence." With a Posthumous Essay on "Instinct," by Charles Darwin. New York: D. Appleton & Co. Pp. 411. Price, $2.
In these systematic studies into the science of mind to which Mr. Romanes has recently appeared as an original contributor, the course of research breaks into three divisions. In the first, "Animal Intelligence," which appeared in the "International Scientific Series," the author devoted himself to the general data of his subject, or to the statement of the basal facts of comparative psychology. The book is chiefly descriptive of mental phenomena as observed in the lower animals, and aims at greater strictness than has hitherto been attained in determining what is trustworthy and what is doubtful among the alleged statements of fact in regard to mental manifestations among the lower creatures. As the volume was, however, a preparation for the study of psychological theories, its facts were chosen with reference to their bearing upon psychological principles to be subsequently investigated; the law of evolution was accepted as the guiding principle of the investigation, but the elaboration of the theory was postponed to a separate work. It was Mr. Romanes's intention to devote his second volume to the general discussion of evolutionary doctrine as displayed in mental phenomena of all orders; but, as he proceeded with the inquiry, materials accumulated, and the subject expanded to such proportions that it became necessary to divide the second part into two treatises—the one devoted to the evolution of mind in the lower animals, and
