132 



The Grayling and the Smelt 



tactile organs (as in Bathypterois and Benthosaurus] , and experi- 

 ments show that barbels may become organs of touch adapted 

 to aquatic life, sensitive to the faintest movements or the 

 slightest displacement, with power to give the blinded fishes 

 full cognizance of the medium in which they live. " 



Rondeletiidae. The Rondeletiida are naked black fishes with 

 small eyes, without adipose fin and without luminous spots, 



FIG. 91. Cetomimus gittii Goode & Bean. Gulf Stream. 



taken at great depths in the Atlantic. The relationship of these 

 fishes is wholly uncertain. 



The Cetomimidaz are near allies of the Rondeletiidcs, having 

 the mouth excessively large, with the peculiar form seen in the 

 right whales, which these little fishes curiously resemble. 



Myctophidae. The large family of Myctophida, or lantern- 

 fishes, is made up of small fishes allied to the Aulopida, but 



FIG. 92. Headlight Fish, Diaphus lucidus Goode and Bean. Gulf Stream. 



with the body covered with luminous dots, highly specialized 

 and symmetrically arranged. Most of them belong to the 

 deep sea, but others come to the surface in the night or during 

 storms when the sunlight is absent. Through this habit they 

 are often thrown by the waves on the decks of small vessels. 



