REGARDING our comment about the incongruous grouping of small mammals in certain cases in the Museum of the Academy of Natural Sciences of Philadelphia (July 16, 1932, p. 90), Mr. Leigh Mitchell Hodges, public relations director of the Academy, writes to say that the sole purpose of the cases in question was to bring together the outstanding examples of the small mammals common to Pennsylvania and New Jersey. No effort was made to exhibit them in their natural surroundings, the grouping being simply a convenient aggregation primarily for the education of school children. Nevertheless, the introduction of a certain amount of ‘environment’ might suggest to children the definite association in Nature of species not usually found together, and this possibility is what we had in mind. In the Museum as a whole, as is well known, great progress has been made in the development of habitat groups, the large cases illustrating lions, Kodiak brown bears, Stone's sheep, and Rocky Mountain goats being particularly fine examples of such exhibits. During the present year, groups of musk-oxen and whistling swans have been constructed, and the programme for the future includes cases of the giant sable antelope, African animals at a water-hole, and the giant panda of Tibet.