Reighard. — Senses and Learning in Fishes 153 



light seems to come from the direction in which it is 

 travelling when it reaches the fish's eye. Therefore the 

 point below 7 on the emergent part of the rod appears 

 to be near 7a, and the points above it at 1 and 4 seem 

 to be at la and 4a as shown in the figure. It results that 

 so much of the rod as is visible above water appears to 

 be higher up than it really is. As shown in the figure 

 each of the visible subdivisions of the rod appears short- 

 ened and the lower ones are more shortened than the 

 upper, as may be seen by comparing the division below 

 6 to that below 6a. Only objects near T are seen in their 

 natural proportions. 



Figure 2. View of objects above and below water as they appear 

 to a fish. Explanation in text. Modified from Vigueron, 1913. 



