by the Regents in 1925 was put into full operation. Ruthven became Director of the University Museums as well as Director of the Museum of Zoology, with supervision of the Museums Building, its common services, and the interrelations of the four independent museums. Each of these museums had its own staff and director and was free to work out its own co-operative arrangement with the teaching departments in its particular discipline, while all shared as museums the common problems that came with the responsibility for the curatorial care of active research and teaching collections. The responsibility for the revived exhibit program was for some years left to the individual museums. With the occupancy of the new building, Crystal Thompson, a former staff member of the Museum of Zoology, was recalled from Amherst, where she had gone to develop the Amherst College Museum, to be Curator of Extension Work and Exhibits in the Museum of Zoology. She developed exhibits and loan collections in zoology and initiated both the exhibit of Michigan fauna on the third-floor balcony and the Hall of Biological Principles on the fourth floor. At the same time the paleontological exhibits were organized as the Hall of Evolution under the direction of Ermine C. Case, the Director of the Museum of Paleontology.
In 1929 Ruthven resigned the directorship of the Museum of Zoology to accept the presidency of the University but retained the directorship of the University Museums until the increasing burden forced him to relinquish all direct relations with the Museums in 1936, when Carl Eugen Guthe, Director of the Museum of Anthropology, was appointed Director of the University Museums. Guthe resigned the directorship of the University Museums and of the Museum of Anthropology in 1944 to accept the directorship of the New York State Museum at Albany, where he succeeded Charles C. Adams, who had been Ruthven's predecessor as Curator of the University Museum. Upon Guthe's resignation a somewhat different plan of administration was adopted for the University Museums. The functions of the director were transferred to an Operating Committee comprised of the directors of the four museums (and, from 1944 to 1950, of the Director of the Laboratory of Vertebrate Biology).
In 1947, in a reorganization of the exhibits program, the position of prefect of exhibits was established to provide a supervisor responsible to the Operating Committee for the combined exhibit program of the four University Museums. Irving G. Reimann was brought from the Buffalo Museum of Science to assume this position, and funds were provided for a small but efficient staff of technicians, artists, and docents. The results of this program are now increasingly evident as each year has shown good progress in the number and quality of the exhibits.
In the accounts of the constituent museums are described the parts which each has played in the development of the University Museums. The year 1928 marked the beginning of a new era of opportunity and productivity for them. As collections grow, questions of selectivity and direction become increasingly important. Accessions which at an earlier stage filled important needs for taxonomic or distributional representation must be scrutinized in the light of whether the additional data they provide justify the space they occupy and the time their processing entails. The existing collections, the maturing concepts of cognate fields, and the proposed research and teaching problems of the staff become increasingly important in shaping the policies and
