barriers be hewn to, such as those of climate, seacoasts, rivers, brush lands and deserts. The forest ranger in anticipating the sweep of a potential fire, or in combating any actual fire, outlines his campaign irrespective of any but those lines which will naturally aid most in stopping the spread of the conflagration.
15. If "drive weeks" be advocated, as a popular measure to secure control locally, the time of the year selected should be fixed in accordance with the optimum chances for success, on the grounds of avidity of the squirrels for kinds of bait available, minimum natural population (previously to the time of appearance of the young), and probable weather conditions.
16. The above general remarks must not be construed as in any degree intended to discourage the continued energetic application of the best methods of ground squirrel control now in use. But it is hoped the facts and inferences set forth will convince the reader that the problem is not a simple one, and cannot be solved by casual, half-hearted measures. It is believed that great improvement can be secured both in devising of method and in mode of application.
LITERATURE CITED.
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1908.The Biota of the San Bernardino Mountains. Univ. Calif. Publ. Zool., vol. 5, pp. 1–170, pls. 1–24.
1913.A Distributional List of the Mammals of California. Proc. Calif. Acad. Sci., 4th ser., vol. 3, pp. 265–390, pls. 15, 16.
1914.An Account of the Mammals and Birds of the Lower Colorado Valley with Especial Reference to the Distributional Problems Presented. Univ. Calif. Publ. Zool., vol. 12, pp. 51–294, pls. 3–13, 9 figs. in text.
1918.Six new Mammals from the Mohave Desert and Inyo Regions of California. Univ. Calif. Publ. Zool. vol. 17, pp. 423–430.
Grinnell, J., and Grinnell, H. W.
1907.Reptiles of Los Angeles County, California. Throop Inst. Bull., no. 35, 64 pp., 23 figs. in text.
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