Certain Reactions to Color in the Young Loggerhead Turtle. 73 



may be divided into three parts, A, B, and C, with the following condi- 

 tions for each: 



Series A. — East side of island (fig. i, c), bushes cut from the interior 

 of the island were stuck into the sand in an upright position to form a 

 semicircle with a diameter of about 5 feet. The water line was tangent 

 to the mid-point of the arc's circumference, about 2 inches from it. 

 A sand barrier, 6 to 8 inches high, was erected just inside the bushes to 

 prevent immediate sight of the ocean. There was a fairly heavy surf 

 and the sun was in the west. 



Series B. — ^The same conditions prevailed as for series A, except 

 that the sun was in the east. 



Series C. — -West side of island (fig. i, d). The conditions of series 

 A were duplicated. The sun was in the east. 



Twenty-four turtles were used in these three series, each one given 

 four trials, headed successively north, west, south, and east. Without 

 exception or even hesitation, all turned away from the bushes and went 



Fig. I.- — Northern end of Loggerhead Key, Tortugas. 



up an incHne of 30° away from the water. Their negative response was 

 continued long after the ocean was in sight, but all the turtles, after 

 going from 8 to 10 feet directly up the slope, made a wide detour and 

 started for the ocean, giving the bushes a wide berth. The position of 

 the operator was an entirely negligible quantity so long as he remained 

 perfectly quiet. 



The next series of experiments was performed in location fig. i, c. 

 The bushes were removed, and the barrier moved back so that it was 

 washed by the waves. A piece of colored glass, 2 feet 6 inches long by 

 18 inches high, was forced into the sand in an opening in the middle of 

 the barrier in such a manner that the sandy floor inside was on a level 

 with the water outside and separated from it only by the glass. The 

 barrier aroimd the ends of the glass and up the slope of the shore for a 

 few feet kept the water out of the semicircular inclosure. The young 



