202 THREE CRUISES OF THE " BLAKE." 



On the loth of July, in Lat. 34° 28' 25" N., Lon. 75° 22' 50" 

 W., we tried the Sigsbee cylinder for a third time, in a depth 

 of 1,632 fathoms. With the same precautions before and 

 after using it, the cylinder was operated first between five and 

 fifty fathoms (time 30"). The water was somewhat ruffled, and 

 but little was found on the surface beyond a few crustacean 

 larvas and heteropods. The cylinder contained hydroids, frag- 

 ments of siphonophores. pelagic algse, crustacean larvae, and het- 

 eropod eggs ; forms which differed from those gathered at the 

 surface, but were identical with the species obtained on previous 

 days under more favorable conditions of the sea. Next, the cyl- 

 inder was arranged for a depth of between fifty and a hundred 

 fathoms (time of messenger 21" from surface to fifty fathoms, 

 time of cylinder 40" to stopper from fifty to a hundred fath- 

 oms). The water was found to contain only a couple of 

 Squillse larvse, similar to those fished up at the surface. The 

 third time the cylinder went down at this station, it was lowered 

 to collect from a hundred to a hundred and fifty fathoms (time 

 of messenger from surface to a hundred fathoms 45", time of 

 cylinder in passing from a hundred to a hundred and fifty fath- 

 oms 45"). The water when examined contained nothing. No 

 radiolarians were found at this station, either at the surface or 

 at any depth to which the cylinder was lowered (one hundred 

 and fifty fathoms). 



The above experiments appear to prove conclusively that the 

 surface fauna of the sea is really limited to a comparatively 

 narrow belt in depth, and that there is no intermediate belt, 

 so to speak, of animal life, between those living on the bot- 

 tom, or close to it, and the surface pelagic fauna. It seems 

 natural to suppose that this surface fauna only sinks out of 

 reach of the disturbances of the top, and does not extend 

 downward to any depth. The dependence of all the pelagic 

 forms upon food which is most abundant at the surface, or near 

 it, would naturally keep them where they found it in quantity. 



The experiments in using the tow-net at depths of five hun- 

 dred to one thousand fathoms, as was done by Mr. Murray 

 on the " Challenger," were not conclusive, as has been already 

 pointed out on a former occasion, while the so-called deep-sea 



