STERNOPTYCIIOIDS. 231 



Brownish, with seven transverse bands of brown, wider than the spaces 

 by which they are separated, crossing the body and fins. 



PHYSOSTOMI. 



STERNOPTYCIIOIDS. 



In 1887, the date of the " Challenger" Repoi't, the position of the Ster- 

 noptychidaj among the deep sea fishes was somewhat questionable. To-day 

 it is yet undecided whether the fishes of this fixmily are really taken at the 

 great depths assigned to them. As they may enter the dredge anywhere 

 on its way np or down, the actual depth of capture will have to be deter- 

 mined in the future by means of appliances opening and closing at j^'ii'ticu- 

 lar intermediate depths between the bottom and the surface. The only 

 present knowledge of conceded value relating to the habitat is based entirely 

 on inferences. Firmness of structure is suggestive of a life near the surface 

 and the large eyes and the luminous organs with that structure point toward 

 a life in comparative darkness or to nocturnal habits, as was suggested by 

 Giinther. To its uttermost limits sunlight reaches down in the sea a 

 hundred and eighty fathoms, more or less, and it may be questioned 

 whether the upper life-area of the ocean extends much farther down. At 

 the bottom there is another area of life and light, the phosjihorescent, in ver- 

 tical extent probably much less than that at the surface, possibly limited to 

 less than thirty fathoms. Wiiere the sea is less than two hundred fatlioms 

 or thereabout it is probably lighted and full of life, other condition? being 

 favorable, from top to bottom, but where the depth is greater the two areas 

 of light are separated by a dark area the depth of which varies according to 

 the total ocean depth at the particular locality. Though the dark area 

 may be traversed in any direction, and though no doubt near its limits it 

 serves as a hiding or lurking place for the preyed upon and for the preda- 

 cious, it is rather doubtful whether otherwise it is permanently inhabited. 

 All things considered it appears likely that many of the Sternoptychida3 do 

 not descend much beyond the reach of the sunlight, a conclusion independ- 

 ently reached from study of the colors, which latter are those of pelagic ani- 

 mals, or those of the surface, rather than tliose of great depths (see Plate J). 



