WILFRED HUDSON OSGOOD was one of the leaders of his generation in the zoological exploration of the two Americas and one of the most influential of museum curators in an era of phenomenal expansion of museums of natural history. He was a survivor of a golden age of systematic zoology in North America, and even through the radical changes of emphasis in modern zoology he commanded the respect of his colleagues in universities as well as in museums. American zoology was enriched by his th?ughtful and permanently useful con- tributions, some of which have had a long-continuing influence in ecology and genetics. Even his short papers describing new species were organized and reflective of sound judgment based on command of the whole range of systematic mammalogy. It becomes those of his successors who knew him best to reflect on his career, to examine its meaning, and to subject it to thoughtful analysis for the lessons derivable from it. It is not the purpose of this essay to attempt a critical evaluation of the man and of his influence, which will find an appropriate place in a history of American natural history museums, when that is written. Though his reputation was mainly in mam- malogy, he could by no means forget his first love---ornithology--and from his election as a Fellow of the American Ornithologists' Union, it was clear that this collateral interest was recognized and appreciated by his ornithological contemporaries and friends. The young naturalist-to-be was the eldest son in a New Hampshire family. The family was of old New England stock, the first Osgood having come to America from England in 1633. On his mother's side, his ancestry was also English, and Wilfred seems to have been in- fluenced especially by a maternal uncle, Charles Harker. In 1883, when he was twelve, the family with its five children, and including Charles IIarker, transplanted itself to a fruit farm in the central valley of California, near Santa Clara. If there be regional differences among the inhabitants of the United States, Wilfred Osgood remained a New Englander. His father and grandfather were watchmakers, and it is not difficult to see something of the watchmaker's habits of precision and attention to detail in their son and grandson. Tle ten years in the west, however, included Wilfred Osgood's high- school career, a year of school teaching in Arizona, and his college years at the University of the Pacific and at Stanford; they could not fail to leave their stamp on his character, and Californian influences clearly governed the direction of his career. He valued his association with the young collectors of birds' eggs who formed the nucleus of the Cooper Ornithological Club--among them Chester Barlow and Rollo H. Beck. At Stanford University, then newly established, he came under the influence of Charles H. Gilbert in the Department of Zoology, and in contact with David Starr Jordan, Stanford's first president, one of the more redoubtable "Old Bisons" of the zoological world of the eighteen nineties. At Stanford, Wilfred Osgood formed what was to be a deep and lifelong friendship with Edmund Heller, whose later travels as a zoological collector were even more extensive than his own. Wilfred Osgood and Edmund Heller were associated in the field in 1900 in faunal studies on the Queen Charlotte Islands and in the Cook Inlet region of Alaska. Before completing his undergraduate work at Stanford, at the age of 22, young Osgood joined the expanding staff of the Bureau of Eco- nomic Ornithology and Mammalogy, of the United States Department of Agriculture. This organization, later to become the Bureau of Biological Survey, was under the dynamic if erratic leadership of C. IIart Merriam. Osgood's first formal field work, in 1898, was on Mt. Lassen and Mt. Shasta in company with Merriam, Vernon Bailey, and W. K. Fisher. Merriam's vision of a biological survey of the North American continent afforded a program sufficiently challenging to capture the imagination of an aspiring young biologist, to stimulate his ambition, and to hold his loyalty. When Osgood went to Washington, at the age of 23, he lived in the Merriam home for some years, half as ap- prentice, half as valet. He gracefully and tactfully acknowledges his debt to Merriam in a biographical memoir, which gives a critical and thoughtful estimate of this remarkable personality. It seems evident that young Osgood learned what not to do quite as much as what to do from the example of his chief. In the Merriam home he came in con- tact with many of the great and near-great of the Washington scien- tific world, and among his associates in the Survey he formed his deepest friendships. The principal outward events of his twelve years with the Biological Survey were his continuing travels in western and northern North America. These gave him a command of the geography of the conti- nent and especially of Alaska. In this period fell the preparation of two systematic reviews of genera of rodents. The first of these, the 'Revision of the pocket-mice of the genus Perognathus' (1900) was really a preliminary exercise, preparing him for the attack on the 27,000 specimens to be examined for the monumental 'Revision of the mice of the American genus Peromyscus' (1909). More than any other work, this established Osgood's reputation. With critical and scholarly care he untangled what had become a snarl of inadequate descriptions and classifications, and produced an arrangement of the recognizable species and subspecies of the small rodents known familiarly as deer-mice or white-footed mice that has stood the test of forty years of use. This work, which came before the introduction of statistics, was far in advance of its time as a study of variation and of what has now come to be called "speciation." It formed the foundation for the crucial biological experiments of Charles B. Sumner; these proved that the quite trivial differences of coat-color and denti- tion and skull form that characterize the subspecies of Peromyscus are heritable. Thus when the subspecies are correlated with peculiar types of environment, their characteristics must have become fixed by genetic drift or by natural selection, and have not resulted from the direct (Lamarckian) effects of the environment. Nor was this the last of the reverberations of the "Revision of Peromyscus." The Laboratory of Vertebrate Biology at the University of Michigan, under Lee R. Dice, has picked up the threads of the speciation question where Sumner left off, and, together with attack on many other problems, has applied ecological experiment to the question of how and why the species and subspecies of white-footed mice differ as they do. With the rich, double experience of wide travels as a zoological collector and sound scholarly studies of the accumulated collections, Wilfred Osgood came to the still young Field Museum of Natural History in Chicago in 1909. As the result of a comedy of errors, he came to replace his friend Heller, who had left the Museum's Depart- ment of Zoology to join Theodore Roosevelt in his tast African txpedition for the Smithsonian Institution. The new curator's first duties were, in fact, to describe the smaller mammals collected by Heller in tast Africa on an earlier expedition for the Chicago Museum. The first "lxpedition" (the museum euphemism for field study and collecting) for the Field Museum took him to Colombia and Venezuela in 1911, and this set a pattern of interest in the mammals of South America that continued to the end of his life, and found expression in numerous descriptions of new species of mammals and in faunal papers. Of these the most notable is 'The Mammals of Chile,' published in 1943, twenty-one years after his first trip to that country in 1922. Like American museum zoologists in general, Wilfred Os- good alternated active travel, collecting, and observation in the field with intensive studies in the laboratory and the preparation of reports on the collections made. As his work for the Biological Survey had made him an authority on the geography of Alaska, and especially an authority on its bird and mammal faunas, so his six major trips to South America for the Field Museum (now Chicago Natural History Museum) made him the acknowledged leader in the mammalogy of that continent. The record of these expeditions has been set forth elsewhere by his colleague and successor in the Museum's Division of Mammals, Colin Campbell Sanborn. As the Bachelor's degree from Stanford had to be granted in absentia because he was already launched  as an undergraduate on what was to be his life work, so also the ?h.D. degree from the University of Chicago came late and was merely incidental to a research career. His thesis was the 'Monographic Study of the American Marsupial Caenolestes,' published by the Museum in 1921 as a full volume in its Zoological Series. This work gave the first adequate account of a remarkabIy interesting creature, at first thought to exhibit direct relations with the Australian marsupials, and important for the light it throws on a great number of extinct genera known from the South American Tertiary. Two major field trips fell outside the South American pattern. The first of these, the Field Museum-Chicago Daily News Abyssinian txpedition was on a properly expeditionary scale, with a distinguished staff, which included the great animal artist, Louis Agassiz Fuertes. A journey into the interior of tthiopia to Lake Tsana was made by camel and horse caravan, departing via the Blue Nile and the Nile. 'The work of the expedition is recorded, in addition to the series of .syndicated reports to the Chicago newspaper, in Dr. Osgood's thought- ful essays in 'Natural History' and in the 'National Geographic Maga- zine,' by the 'Album of Abyssinian Birds' by Louis Agassiz Fuertes, and in 'Artist and Naturalist in Ethiopia' by Fuertes and Osgood, which combined the diaries of the two friends and forms a touching memorial to Fuertes, whose tragic accidental death took place shortly after the return of the party from Africa. The second of the non-American expeditions was a collecting trip to French Indo-China in 1939. This was financed by Dr. Osgood him- .self and was apparently the only major trip on which he travelled .alone. The two major collecting expeditions to Chile dominated the last phase of Osgood's career. These expeditions were focussed on the study and collecting of birds and mammals, with a by-product of .amphibian and reptile collections. In these expeditions, which were in part "On Darwin's Trail," he was engaged in the preparation of a definitive account of the mammals of a faunally definable segment of "Neogaea." The resulting volume, 'The Mammals of Chile,' must be placed with the revision of Peromyscus and the monograph of Caenolestes as a third technical work of major importance. It em- 'bodies an acute study of all the collections available with a scholarly incorporation of past work on the mammalian fauna of Chile. Much of Osgood's fine scholarship was incorporated in the 'Check- list of South American Mammals' which was left unfinished in the hands of his successors in the Division of Mammals at the Chicago Natural History Museum. He was engaged on this check-list and on 'the completion of the Chilean work during his seven years as Curator Emeritus at the Museum. These years, in which he was relieved of the volume of popular writing for the Museum's 'Bulletin' and of the burden of administrative routine, may well have been among the happiest of his life. Osgood's world wide travels were carefully planned and competently ,carried out. They present an aspect of his capacities quite different from that of the popular concept of a scholar. Equally foreign to narrow scholarship was his continued interest in expansion of exhibi- tion in the halls of the Chicago Museum. His regime as Chief Curator .of the Department of Zoology (succeeding Charles B. Cory) coincided with a period of expansion of the museum in the new building to which exhibits and collections were moved in 1921. Whole new halls of habitat groups were planned and finished, and new types of presenta- tion in the systematic halls were devised. The importance of sub- jective aspects of exhibition was thoroughly appreciated by him and was well set forth in essays in the 'Britannica Book of the Year' (1938, 1939) and in the 'Field Museum News.' As to the personal Osgood, he molded a staff that maintained an extraordinary degree of good relations within the museum. His editorship of the scientific papers of the junior members of his staff was extremely competent and helpful, in the matters of content and organization as well as in details of composition. I well remember the difficulty of arguing with him about usage of vernacular zoological terms. He could always refer me to 'Webster's Dictionary' and I only later learned that he had himself written or rewritten the defini- tions. We all envied him the ability to write page after page with scarcely an interlineation. My own relations with Dr. Osgood (as I mostly addressed him) became more and more friendly during our 25-year-long, staff relation- ship. After bringing me to the Chicago Museum, he left me free to develop my career as our resources and my abilities permitted. In this our relations were almost a repetition of those of Dr. Osgood with his own predecessor, as is related in his appreciation of C. B. Cory in an earlier volume of 'The Auk.' When it was arranged that I should succeed him as Chief Curator of the Department, we became still more intimate. We jointly planned to have a few weeks together in the field, in Chile, as part of the 1939 Magellanic Expedition. This plan failed, and it is a matter of deep regret to me that I could not personally know the side of "The Chief" that was well known to his companions in field and camp. At home and in the Museum he was reserved and even aristocratic in temperament. In the field the 'basic simplicity and humility of his character was brought out, reflect- ing, perhaps, his life-long familiarity with mountain and forest and his deep love of the wilderness. His later friendships were largely outside the museum, for he sadly outlived the intimate circle of such early naturalist friends of the Cooper Club and the Biological Survey as Barlow, Hollister, Heller, and Fuertes, who had been his campmates. His social gifts were great, and he was a valued member of the University and University Club circles in which he moved. A bachelor all his life, he exhibited no touch of misogyny and was a favorite in mixed company, notably in a group that engaged in readings of classical and modern dramatic works, with parts assigned to the individual members. His outdoor recreation was mainly golf and fishing, but for his vacations he turned more and more to short field trips for the collecting of the small rodents of which he was so genuinely fond. It is interesting, then, to reflect on the life of a naturalist so typical of his generation. The roots of his career lay in the field-collecting era that produced and was produced by the vogue of private collections of birds, birds' eggs, and mammals. He lived through and played a part in the period of great expansion of the United States Bureau of Bio- logical Survey, which in his day devoted its energies and funds to a program essentially in pure science--the fanhal survey of a continent and the attempt to derive meaning from its results. As head of a Division of Mammals and Chief Curator of a Department of Zoology -in a great museum for thirty years, he helped to make both his De- partment and his Museum great. In the course of his career he acquired more than a specialist's command of his subject, so much so that he should be enumerated among the foremost of mammalogists, not merely of his own time, but of the whole period of the rise of systematic zoology since Linnaeus. Chicago Natural History Museum, Chicago, Illinois, January 7, 1950.