82 The Life Story of the Fish 



eyed fish Anablefs. This creature has eyes divided into two 

 sections, one for seeing in the air and one for seeing in water. 

 Lying habitually at the surface so that the upper half of 

 each eye is in the air, it has to duck its head under water 

 every few moments to freshen up that exposed portion of 

 the eye. 



One of the features of the lid in our eyes is the lachrymal 

 gland. This furnishes the moisture for the proper working 

 of the eye, and also furnishes tears for us when we wish to 

 weep. The fish has no lachrymal gland, and it therefore 

 cannot weep. It is of interest that the human infant cannot 

 weep until it is several weeks old. It can bawl, but not pro- 

 duce tears. No, I am not calling your baby a fishj I am 

 merely pointing out another of the reasons why the biogenetic 

 law fascinates biologists. 



The second difference in the fish's eye is that there is little 

 or no provision for altering the amount of light that enters 

 the pupil. The iris, the colored ring, in our eyes can widen 

 or shrink, leaving only a pin-point in the center when the 

 light is bright, or exposing practically the whole lens when 

 the light is very dim. The fish also has an iris, the metallic- 

 looking ring around the dark circular center, but this iris is 

 practically incapable of movement. Teleologically speaking, 

 we might say that that is because the light under water 

 never attains such brilliance as to make protection against it 

 necessary. 



The next thing which we meet on our way into the fish's 

 eye is the lens, and here we encounter a major difference. 

 Our lens is comparatively flat. It is in shape not unlike the 

 common hand magnifying-glass or "reading-glass." The fish's 

 lens is spherical (see Figure 12). Where our lens is a disk, 

 the fish's lens is a globe. It is, in fact, that unappetizing little 

 white ball which you sometimes find rolling around on your 

 plate when a whole fish is served to you. The lens has come 



