CRAWLING OF YOUNG TURTLES TOWARD THE SEA 327 



almost exactly like that described by Hooker ('11, p. 72) in that 

 I set up the horizontal pen in an open field to the east of a low 

 hedge west of which was a sea-wall and the bay. On liberating 

 the turtles here they all took easterly courses away from the 

 hedge, and incidentally away from the water. Their courses 

 were toward the open field. Evidently, the mass of the hedge 

 and the open field influenced the direction taken much as the 

 laboratory buildings and the open water had done, but in this 

 instance it was perfectly evident that the water had no necessary 

 part in determining this direction. These results agree exactly 

 with those obtained by Hooker. 



I next set up the pen in a square open field, three sides of which 

 were bounded by well-grown trees and the fourth fairly open. 

 The turtles went with reasonable regularity toward the open side. 

 I then transferred the pen to a very open sandy plane and piled 

 up next one side of it a number of boxes and tin cans till a wall 

 nearly a meter high was formed. From this the turtles regularly 

 moved away. These various tests led me to conclude that any 

 large mass interrupting the horizon forms a center from which 

 young loggerhead turtles retreat. 



But these animals not only retreat from conspicuous masses 

 on the horizon ; they also move toward the open horizon with great 

 certaint5^ I was persuaded of this by an accidental observation 

 made while I was testing a very different matter. I had placed 

 the horizontal pen between and in front of two well-grown bushes 

 to ascertain whether the turtles would orient to one or other of 

 these or give a combined reaction to both. Much to my sur- 

 prise the turtles did not retreat from the bushes, but took a 

 course in the opposite direction as though they were going directly 

 through the opening between the bushes. On looking through 

 this opening I observed what had escaped my attention before, a 

 considerable stretch of free horizon, I repeated this test several 

 times and always with the same result, the turtles took a course 

 between the two bushes. Consequently, I concluded that though 

 young loggerhead turtles move away from large interrupting 

 masses on the horizon, they also move with great certainty toward 

 a section of open horizon even though this may be relatively small. 



