8 bulletin: museum of comparative zoology. 



thermometers were also supplied by him and by Professor Mendenhall, 

 the Superintendent of the United States Coast Survey. I provided myself 

 with a number of self-closing Tanner deep-sea tow-nets, with a supply of 

 dredges and surface tow-nets, and carried on board a Yale and Towne 

 patent winch for winding the wire rope used in dredging and towing in 

 deep water. The yacht was provided with a steam capstan ; by increas- 

 ing its diameter with lagging we found no difficulty in hauling in our 

 wire rope at the rate of a hundred fathoms in eight minutes. We carried 

 six hundred fathoms of steel wire dredging rope of the same dimensions 

 which I had used on the " Blake," and which has also been adopted on 

 the " Albatross." 



Both on going into Havana and on leaving we spent the greater part 

 of a day in towing with the Tanner net. I thought I could not select a 

 better spot for finally settling the vertical distribution of pelagic life than 

 off Havana, which is in deep water — nine hundred fathoms — close to 

 land, on the track of a great oceanic current, the Gulf Stream, noted for 

 the mass of pelagic life it carries along its course. "We towed in one 

 hundred, one hundred and fifty, two hundred and fifty, and thi-ee hun- 

 dred fathoms, and on the surface at or near the same locality, and I have 

 found nothing to cause me to change the views expressed in the Prelim- 

 inary Reports of the " Albatross " expedition of 1891.-^ At no depth did I 

 obtain with the Tanner net any species which were not also at some time 

 found at the surface. Even at one hundred fathoms the amount of 

 animal life was much less than in the belt from the surface to that 

 depth. At one hundred and fifty fathoms there was still less, and 

 at two hundred and fifty fathoms and three hundred fathoms the 

 closed part of the Tanner net contained nothing} At each of these 

 depths we towed fully as long as was required to bring the net to the 

 surface again. Thus we insured, before the messenger was sent to close 



1 Alexander Agassiz: General Sketch of the Expedition of the "Albatross," 

 from February to May, 180]. Bull. Mus. Comp. Znul., Vol. XXIII. No. 1, 1892. 



'-' Tliis is fully in accordance with the observations of the Plankton Expedition, 

 as far as they have been published by Apstein, Ortmann, Giesbrecht, and others, 

 relative to the bathymetrical range of the pelagic fauna. The diminution and final 

 disappearance at sea of pelagic animal and vegetable life below a comparatively 

 narrow limit seems general. That there are local conditions near shore, or in com- 

 paratively closed or shallow areas, or in districts adjoining submarine banks near the 

 500 fathom line, which modify these conclusions, I have already stated. Many of 

 the observations which form the basis of statements proving the indefinite exten- 

 sion in depth of the pelagic fauna and flora, are of little value, owing to the imper- 

 fect working of the apparatus in use. 



