on board H.M.S, 'Challenger.' 537 



1. A region roughly marked out by the northern edge of the JT.E, 

 trade-wind and the southern edge of the S.E. .trade-wind. 



2. A region lying along the coasts of great islands and continents, 

 where we have usually a mixture of fresh and salt water. 



3. A region in the Southern and Antarctic Oceans south of the latitude 

 of 50° S. 



In all depths less than 1500 fathoms there would seem to be a direct 

 relation between the organisms occurring on the surface and the deposits 

 taking place on the bottom. Where we have Diatoms on the surface, 

 there we have their frustules on the bottom. Where we have Glohi- 

 gerina and Pteropods &c. on the surface, there also we get their dead 

 shells or broken parts of them ; and so also for the Eadiolaria, Cocco- 

 spheres, and other organisms. In some areas within the depths referred to 

 we occasionally do not find the remains of some of the surface organisms 

 so numerous as we should expect. In these cases, however, I suspect 

 they are rather masked or obscured by an abundance of shore debris 

 than removed from the deposit. 



When we consider the specimens of the bottom from depths greater 

 than 1500 fathoms, the relation is by no means so constant. It still 

 holds good that when pelagic Foraminifera, Pteropods, Diatoms, Eadio- 

 laria, or Coccoliths are found on these bottoms, the same varieties of 

 each of these are found on the surface ; but perhaps in the majority of 

 bottoms, in depths greater than 1500 fathoms, the exuviae of some or all 

 of the organisms found on the surface are partially or wholly absent. 

 When these have been carefully reexamined, the results tabulated and 

 compared with other observations recorded at the same place, it is likely 

 some light will be thrown upon the subject. 



3. Preliminary Eeport on Vertebrates. 



Of the Vertebrate animals collected during the cruise, the chief interest 

 is very naturally attached to those fishes on which our special investigations 

 might be expected to give some information. Many specimens have been 

 taken in our trawlings and dredgings. Other than the British Museum 

 Catalogue, we have with us no literature on this subject. Many of the 

 specimens which we regard as new may be described, and' some of those 

 which are believed to be identical with described species may turn out to 

 be distinct ; therefore for the present it is considered best to give a list 

 of the fishes, with the determinations which were made at the time of 

 their occurrence, and not to cumber this Eeport with descriptions. 



Besides the fishes taken in the trawl and dredge, many small larval 

 and adult forms have been obtained in the tow-nets. These last have 

 chiefly been preserved as microscopic preparations. In every case notes 

 have been taken at the time the specimens were procured, and all have 

 been labelled and preserved with great care. 



