220 THE ZOOLOGIST. 



Jn series : 30 ctim., thirteen went over and five refused. 

 80 ,, eleven refused and five went over. 

 30 ,, eleven went over and six refused. 



If the animal is able to judge when it is as high as 180 ctim., 

 as the evidence points, it probably does so by sight. All the 

 animals, if hesitating, spent their time in looking down and 

 around. At 180 ctim., perhaps, they are able to see nothing at 

 all beneath them. In the middle distances they can see the 

 floor, and therefore fling themselves over when in normal con- 

 dition, but no judgment is formed as to the varying height of 

 these middle distances. The low heights they are perhaps able 

 to see distinctly, and therefore to form an elementary judgment. 



In such a slight power of judgment we see something upon 

 which the forces of evolution could act, if necessary. But the 

 fact of the matter is that, so far as I am able to understand the 

 Newt's feeling by observing its outward actions, a fall of 180 ctim., 

 even when repeated several times in immediate succession, has 

 no effect upon it, except perhaps a little temporary discomfort. 



The hopping Frog has to take "pot luck" as to where it is 

 ' going to land itself, and there is, of course, no hesitation in that 

 animal in jumping over a precipice, if one got in its way. The 

 Toad, if it is crawling, is always brought to a standstill by the 

 edge of a board. It is curious to observe in this animal, and 

 more especially in the Newt, how frequently it went to the edge 

 of a board without realizing it until the non-contact stimulus of 

 one of its feet attracted its attention, and it immediately looked 

 down. 



It has been shown* that land -dwelling Tortoises crawl over 

 30 ctim. without reluctance. Water Tortoises plunged off with- 

 out hesitation, but at a height of 90 ctim. hesitated slightly. 

 Amphibious Tortoises hesitated at 30 ctim., and at 90 ctim. 

 showed more hesitation and reluctance. 



XL 

 The Newt, in both species, has a strong stereoscopic reflex. 

 It is surprising to observe the strength it is able to employ in 



* Dr. Yerkes : " Space Perception in Tortoises," ' Journal of Comparative 

 Neurology and Psychology,' vol. xiv. p. 17. 



