. Elementary textbook of economic zoology and entomology. Zoology; Insect pests. ONE-CELLED ANIMALS 33 animals to appear on the earth, and as ocean life is older than terrestrial life it is probable that certain marine Protozoa are the most ancient of all animals. Some of these marine Protozoa, as the Foraminifera and the Radiolaria, secrete a tiny shell of lime or silica which encloses most of the body. When these animals die their shells sink to the bottom where, as they slowly accumulate, they form a thick layer over the floor of large areas of the ocean. The. FIG. ii.—A marine Protozoan, R
. Elementary textbook of economic zoology and entomology. Zoology; Insect pests. ONE-CELLED ANIMALS 33 animals to appear on the earth, and as ocean life is older than terrestrial life it is probable that certain marine Protozoa are the most ancient of all animals. Some of these marine Protozoa, as the Foraminifera and the Radiolaria, secrete a tiny shell of lime or silica which encloses most of the body. When these animals die their shells sink to the bottom where, as they slowly accumulate, they form a thick layer over the floor of large areas of the ocean. The. FIG. ii.—A marine Protozoan, Rosalina variant (Foraminifera), with calcareous shell. (Greatly magnified; after Schultze.) ooze thus formed is called Foraminifera ooze or Radiolaria ooze, according to which order of Protozoa chiefly formed it. All over the world are found great strata of rocks that are formed almost exclusively of the fossil shells of these Protozoa. The extensive chalk beds and cliffs of England, France, Greece, Spain and America were made by Foraminifera, whose shells were deposited there when these places were parts of the ocean beds. The siliceous rock called Tripoli, found in Sicily, and the Barbadoes earth from the island of Barbadoes are composed of the shells of ancient Radiolaria. 3. 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 Kellogg, Vernon L. (Vernon Lyman), 1867-1937; Doane, Rennie Wilbur, 1871-. New York, H. Holt and company
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