FINNT LIOHT-BEABERS. 91 



CHAPTER XII. 



FINN^ LIGHT-BEARERS. 



IF it were possible for human beings to penetrate to the 

 abyssal depths of the ocean, finny torch-bearers would be 

 found from the very surface to nearly four miles beneath it ; 

 existing in many cases under conditions almost incomprehen- 

 sible when the enormous attendant pressure is considered. 

 While it is extremely difficult to tell the exact depth from 

 which a fish is taken by the dredge, sufficient data has been 

 secured for naturalists to assume, though there is great differ- 

 ence of opinion, that, to a greater or less degree, the forms 

 of certain depths have certain peculiarities. These are often 

 seen in the organs of vision, which have been modified in 

 many ways by the lack of light. Thus the eyes of forms 

 that are found living five or six hundred feet below the sur- 

 face are often extremely large, as in Beryx (Plate XVIII., 

 Fig. 1), as if to absorb the faintest beams of sunlight that 

 may penetrate this distance. As we descend to twelve hun- 

 dred feet, the eyes seem to grow larger; and beyond this, 

 large and small eyed fishes are found indiscriminately. The 

 former evidently use these organs ; while those with small 

 ej'^es are provided with remarkable organs of touch, — long 

 feelers which can be thrown forward, or moved to a more 

 or less extent, and used as the blind man uses his cane. An 



