170 The Under Water-World 



another deep-sea fish (Chauliodus) 140 

 mm. in length. This apparently impos- 

 sible swallowing feat is explained by 

 Regan as follows : " The Chauliodus was 

 seized by the middle and was swallowed 

 double until it reached the posterior end 

 of the stomach, when the head and tail 

 still protruded from the mouth of the 

 captor. These were then taken in and 

 bent back until the whole fish, now 

 doubly folded, was in the stomach of the 

 Gigantura. Digestion affected the part 

 first swallowed where the flesh had quite 

 disappeared, exposing the vertebral 

 column for a length of 18 mm. 



Most of these deep-sea fish have the 

 eyes enormously developed, but others, 

 like certain burrowing mammals and 

 reptiles have paid the penalty of neg- 

 lecting to use their eyes by all but losing 

 them. Again, in certain fish inhabit- 

 ing dark caves, the eyes are almost or 

 even entirely absent. The underground 



