. Relics of primeval life, beginning of life in the dawn of geological time. Biloculina. A many-chambered Fora- Polystotnelia. A spiral^ Foraminifer. niinifer. Magnified as a transparent Magnified as an opaque object,object. Fig. 46.—Recent Protozoa. is more especially evident in their tests or cover-ings, made for the most part of limestone orcalcium carbonate, but sometimes of grains of fine THE DAWN OF LIFE 177 sand cemented together. These coverings arealways perforated with at least one orifice for theemission of the thread-like processes or pseudopods,and often with a vast number of smal
. Relics of primeval life, beginning of life in the dawn of geological time. Biloculina. A many-chambered Fora- Polystotnelia. A spiral^ Foraminifer. niinifer. Magnified as a transparent Magnified as an opaque object,object. Fig. 46.—Recent Protozoa. is more especially evident in their tests or cover-ings, made for the most part of limestone orcalcium carbonate, but sometimes of grains of fine THE DAWN OF LIFE 177 sand cemented together. These coverings arealways perforated with at least one orifice for theemission of the thread-like processes or pseudopods,and often with a vast number of small pores forthe same purpose. Sometimes the test or shell issmooth, sometimes beautifully sculptured exter-nally. Sometimes it consists of a single chamberlike a ball or vase. More often, as the animalsincrease in size, they form additional chambers,and the body thus becomes divided into lobesconnected with each other by necks passing throughorifices in the partitions. The chambers are ar-ranged in rows or in spirals, and in other ways^giving a vast variety of forms, oft
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Keywords: ., bookauthordawsonjohnwilliamsir1, bookcentury1800, bookdecade1890
