. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. 566 DEPTHS OF THE OCEAN Norwegian Fig. 392. Ajtlographispandora, Haeckel (about -\0-). (From Haecker.) distribution of these forms, and found the small one (var. typica) occur- ring in all depths, the large one (var. bathybid) in depths between 400 and 1000 metres; ^r- f the giant form occurs very rarely i n fjords. The Challenger- idae have an egg or lentil-shaped silici- ous shell of mos
. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. 566 DEPTHS OF THE OCEAN Norwegian Fig. 392. Ajtlographispandora, Haeckel (about -\0-). (From Haecker.) distribution of these forms, and found the small one (var. typica) occur- ring in all depths, the large one (var. bathybid) in depths between 400 and 1000 metres; ^r- f the giant form occurs very rarely i n fjords. The Challenger- idae have an egg or lentil-shaped silici- ous shell of most delicate structure, the aperture being provided with a collar or tube- shaped moulding (see Fig. 394). They occur in all oceans, but some- times their distribu- tion is very peculiar, for some species live only in abyssal depths under the equator, others at both poles, others only in Antarctic waters ; some species live in the sur- face waters, others between 50 and 400 metres, others between 400 and 1000 metres, others again between 1500 and 5000 metres. From Haecker's report on the Radiolaria of the " Valdivia " Expedi- tion we reproduce some of these species. Protocystis (Challengeri a) tridens (Figs. 394, 2 and 3) occurs in the northern and south- ern cold zones, having been taken as far north as Spitsbergen, in the Norwegian fjords, the Skagerrack, round Green- land, in the Labrador cur- rent, and also in Antarctic waters by the " Valdivia " ; in Norwegian waters it has been taken in deep water up to 50 metres below the surface. P. swirei (Fig. 394, 1) has been taken only in the Antarctic from the surface down to a depth of 4000 and 5000 metres. P. tJiomsoni (Fig. 394, 4) belongs to a group of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Murray, John, Sir, 1841-1914; Hjort, Joh
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