462 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1910. 



elude that the floating life of the surface of the sea does not sink to 

 a depth greater than 200 fathoms, and that the bottom forms of the 

 deep sea do not rise more than 60 fathoms above the floor of the 

 ocean, and that there is practically no life between 200 fathoms be- 

 low the surface and 60 fathoms above the bottom. His later studies 

 have, however, shown that these conclusions must be modified, for 

 in the tropical Pacific surface forms are sometimes taken at a depth 

 of about 300 fathoms beneath the surface, and although the surface 

 animals do not commonly sink to depths greater than this, there is 

 apparently a most interesting intermediate fauna of medusEe, etc., 

 which are sometimes found at depths greater than 400 fathoms, and 

 which rarely or never rise to the surface. Agassiz clearly saw the 

 complexities and difficulties of this problem and realized that its so- 

 lution can be reached only after many have labored upon it. In- 

 deed, he himself was forced through lack of time to abandon its 

 study to others. 



A very rich collection of deep-sea forms then new to science was 

 made by this expedition of the Albatross^ and have been described in 

 numerous papers in the " Bulletins " and " Memoirs " of the museum 

 at Harvard. 



The most important general result was Alexander Agassiz's dis- 

 covery that the deep-sea animals of the Gulf of Panama were more 

 closely allied to those of the depths of the Caribbean Sea than the 

 Caribbean forms were to those of the deep waters of the Atlantic. 

 This leads him to conclude that the Gulf of Panama was once more 

 intimately connected with the Caribbean than the latter is with the 

 Atlantic, and thus the Caribbean Sea was at one time merely a bay 

 of the Pacific, and has become shut off since Cretaceous times by the 

 uplifting of the Isthmus of Panama. 



In 1892 Alexander Agassiz published his general report upon this 

 important exploration of the Panamic region, and he concludes that 

 the Galapagos Islands have never been connected with the mainland 

 of America, but that the ancestors of their peculiar animals and 

 plants were drifted over the ocean by the prevailing winds and 

 stranded upon the shores of these remote islands. He also observ^ed 

 that the animals of the deep-sea are preponderatingly reddish or 

 violet in color, and that blue-colored forms, such as are observed 

 on the surface, are rare in the depths. This inclines him to suspect 

 that the lingering remnant of sunlight which penetrates into the 

 depths is red, but in view of the absence of observation he is cautious 

 in advancing this suggestion. 



Another paper of 1892 is his description of an interesting crinoid 

 from the depths of the sea near the Galapagos Islands. This is a 

 highly generalized form, and it is beautifully painted from life by 

 Westergren, who accompanied him as artist upon the Albatross. 



