22 



THREE CRUISES OF THE " BLAKE. 



Fig. 195. Sternoptyx diaphana. 



a haul in mid-ocean, is entirely at a loss to know where his cap- 

 tures have been made. If he has taken a flounder from a haul 

 in 800 fathoms, or finds a macruroid, a brotuloid, a berycoid, a 

 synodontoid, or a nemichthyoid in a net which has been below 



the two-thousand- 

 fathom line, he feels 

 tolerably sure that he 

 has brought it up 

 from the bottom. 

 But who shall say 

 where those which 

 like Argyropelecus, 

 Sternoptyx (Fig. 

 195), or Cyclothone 

 (Fig. 196), having al- 

 lies among the pela- 

 gic fishes in the same 

 net, have come from ? They may have come from the bottom, or 

 they may have become entangled in the meshes of the trawl when 

 but a few fathoms below the surface, in its ascent or descent. 

 Many of the deep-sea fishes undoubtedly lead a most active life 

 in spite of their cartilaginous bones and feeble muscular system, 

 being kept efficient perhaps by the enormous pressure under 



which they live. The abso- 

 lute calm of the abyssal re- 

 gions may be the cause of the 

 extraordinary development of 

 some of the tactile or other 



Fig. 196. Cyclothone lusca. t- (U. S. F. C.) . 



organs 01 sense occurring in 



different parts of the skin, usually on the head or upon the 

 lateral lines ; some of these may be, as has been suggested by 

 Leydig, accessory eyes, or phosphorescent organs. The acces- 

 sory eyes may perform the part of bull's-eyes, thus constituting, 

 according to Dr. Giinther, " a very deadly trap for prey, one 

 moment shining that it might attract the curiosity of some sim- 

 ple fish ; then extinguished, the simple fish would fall an easy 

 prey." Some of the long filamentous organs are phosphores- 

 cent, while others are merely tactile. 



