22 THREE CRUISES OF THE “BLAKE.” 
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- 
gie 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 
organs of 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, 
aecording to Dr. Günther, *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. 
Fig. 195. — Sternoptyx diaphana. 4. 
Fig. 196. — Cyolothonelusea. }. (U. S.F. C.) 
