33^ SUMMARY AND CONCLUSIONS 



horizontal haul of four hours at any depth produces at the 

 most a pint of plankton and ten to thirty fish, all small, 

 except perhaps one or two twelve inches or so in length. 

 Yet every descent and ascent of the bathysphere showed a 

 fauna, rich beyond what the summary of all our 1 500 nets 

 would lead us to expect. Bermuda is in the Sargasso Sea, 

 which is accounted an arid place for oceanic life, but my 

 observations predicate at least an unsuspected abundance 

 of unknown forms. 



It is notable that my deepest dive was 504 fathoms, and 

 our net trawls at this depth show usually the maximum 

 captures. On almost all the dives there were zones or strata, 

 sometimes of considerable extent, where no life was visible 

 except a few sparks. The unconscious emphasis placed upon 

 these sparks in the telephoned observations often concealed 

 the extent of the successive black voids, which must be of 

 great extent. 



(b) Illumination 



Heretofore we have had three sources of information 

 with regard to the illumination of deep-sea organisms: 



1. Examination of the photophores of preserved or re- 

 cently dead specimens. 



2. Dark room observations on the light of fish brought 

 up alive. 



3. Comparison with luminous terrestrial coleoptera and 

 other forms. 



