REACTIONS OF THE HORNED LIZARD. 113 



Van Denburgh, John 



'123 Descriptions of Three Lizards from California and Lower California with 



a Note on Phrynosoma blainevillei. Proc. Cal. Acad. Sci., IV. 

 'i2b Phrynosoma Solaris, with a Note on its Distribution. Ibid. 

 '120 Notes on a Collection of Reptiles from Southern California and Arizona. 



Ibid. 



'13 The Reptiles of the Pacific Coast and Great Basin. Ibid., Vol. V. 

 '14 A List of New Reptiles from Southeastern Arizona with a Description of a 



New Species of Cnemidophorus. Ibid., Vol. VI. 

 Van Denburgh, John, and Slevin, J. R. 



'13 A List of the Amphibians and Reptiles of Arizona. Ibid., Vol. 7. 

 Visher, S. S. 



'16 The Biogeography of the Northern Great Plains. Geog. Rev., Vol. I., pp, 



89-115. 

 Watson, J. R. 



'n A Contribution to the Study of the Ecological Distribution of the Animal 

 Life of North Central New Mexico with Especial Attention to the Insects. 

 Rep. Natural Resources Survey of New Mexico, pp. 67-117. 

 '12 Plant Geogiaphy of North Central New Mexico. Bot. Gaz., Vol. 54, pp. 



194-217. 

 Weinzirl, John 



'05 Evaporation from Water Surface at Albuquerque, New Mexico. Bull. 

 Hadley Climatological Lab., Vol. III., No. 10. 



CHART I. Showing the reactions of Phrynosoma in gradients of the evaporating 

 power of air. In the experiments illustrated this gradient was established by vary- 

 ing the humidity of the air with which the animals came into contact. The manner 

 in which the gradient was established and the records made was as follows: A 

 rectangular cage approximately 50 cm. X 10 cm. and 5 cm. deep was so arranged 

 that currents of air from different sources could be directed across different sections 

 of the cage. The openings were so arranged that the air passing across a given 

 third of the cage was of uniform character throughout the experimental period, 

 while that in each third differed as to humidity, but in no other way from that in the 

 other sections of the cage. The animal could pass freely from one part of the cage 

 to another. See text for more complete description of the apparatus. In the 

 chart, each section between the numbered scales represents the record of a twenty- 

 minute experiment, the distance between the scales representing the length of the 

 cage, and the vertical length of the chart the time, twenty minutes, each division 

 on the scale representing ten seconds. The curve in this space represents the 

 movements of the animal under observation, and as the time-component is vertical 

 and the space-component is horizontal, the parts of the curve more nearly hori- 

 zontal represent the most rapid movements, while the vertical parts of the curve 

 indicate that the animal was at rest during the length of time indicated on the scale. 

 Thus, in chart za (the fourth from the left), the animal, introduced near the centre 

 of the cage, remains in that position for approximately one minute, and then moves 

 toward the left end of the cage, the movement occupying a period of ten seconds. 

 The lizard remains in this position for a little over twenty seconds, and then moves 

 toward the other end of the cage, where he arrives at the end of the second minute. 

 Here he remains for three minutes, when he again moves toward the left end of the 

 cage. 



