Bathymetric Distribution

Occurrence of organisms with reference to altitude, on land, and depth, in the seas. oceanic distribution this is partly regulated by the depth but more especially by the temperature. The Littoral Zone includes the sea bottom uncovered at low tide. From this to a depth of 15 fathoms extends the Laminarian Zone. Then come the Coralline Zone, which extends from 15 to 50 fathoms, and the Deep-Sea Zone, from 50 to 400 fathoms in depth. Below this is the Aby al Zone. Abundant and peculiar forms exist in the ocean down to 4,000 or more fathoms, including Foraminifera, Radio lari a, Echinoderms, Siliceous Sponges, Fishes, etc. The general ocean surface constitutes the Pelagic Zone, swarming with Foraminifera, Hydrozoa, Pteropods, etc.