THE PHOSPHORESCENT SCOPE LOWS 



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lenger. Possessing an extremely-elongate and cylindrical body, covered with large, 

 thin, deciduous scales, this fish has a depressed head and an elongate, broad, spatulate 

 muzzle, of which the whole upper surface is occupied by a luminous or visual organ, 

 divided longitudinally into halves, and representing the highly-modified eyes. 

 The whole length of this strange fish does not exceed between five and six inches. 

 Another deep-sea fish (Plagyodus} is noteworthy on account of its large dimensions, 

 and the formidable armature of its mouth; the scaleless body being long and com- 

 pressed, the snout much produced, and the teeth of the jaws and palate of very un- 

 equal size, some forming long and sharply-pointed tusks. 



THE PHOSPHORESCENT SCOPELOIDS Families STERNOPTTCHID^E 



and STOMATEID^ 



More or less nearly allied to the scopeloids are two families of deep-sea or 

 pelagic fishes usually bearing phosphorescent organs along the sides of the body; an 

 example of each being represented in the following illustration. 



Silvery 



PHOSPHORESCENT SARDINE. 



(Natural size.) 



The fish (Photichthys argenteus) shown in the upper figure of the 

 "TV illustration, is taken as our representative of the first of the two 



families, of which, in addition to the phosphorescent organs, the 

 leading characteristics are as follows: The body may be either covered with thin 

 deciduous scales, or entirely naked; barbels are wanting; and the fatty fin is either 

 rudimental or of very minute size. Both the premaxillae and maxillae take a share 

 in the formation of the margin of the upper jaw, and bear pointed teeth of variable 

 length. The bones of the gill cover are not fully developed; the gill opening is of 

 great width; false gills may or may not be developed; and, when present, the air 

 bladder is of simple structure. The ovaries are furnished with ducts. Whereas 



