Forming the northeastern border of Mexico, Tamaulipas extends in an elongated, north-south direction from the Temperate into the Torrid Zone and contains faunal elements from both the Nearctic and Neotropical regions. The mammals are less known than those from some of the bordering states; for the most part collecting has been limited to a few localities, chiefly along the Pan-American Highway. Accordingly, as a step towards a long-range study of the mammals of Tamaulipas, the Museum of Natural History of the University of Kansas acquired from William J. Schaldach, Jr., a small, but significant, collection of mammals taken in the last month of 1949 and the first four months of 1950.