. Comparative zoology, structural and systematic. For use in schools and colleges. Zoology. CCELENTERATA. 235 granules. On one side is a slight depression, or "month," leading to a short, funnel-shaped throat. A mouth and a rudimentary digestive cavity are the distinctive features of these Protozoans. They multiply so rapidly (chiefly by self-division), that a Paramecium^ the most common form, may become the parent of 1,364,000 in 42 days. There are two main groups: Flagellata, or Monads, provided with one or two flagella, or long bristle - like cilia; and Ciliata, which are furnishe
. Comparative zoology, structural and systematic. For use in schools and colleges. Zoology. CCELENTERATA. 235 granules. On one side is a slight depression, or "month," leading to a short, funnel-shaped throat. A mouth and a rudimentary digestive cavity are the distinctive features of these Protozoans. They multiply so rapidly (chiefly by self-division), that a Paramecium^ the most common form, may become the parent of 1,364,000 in 42 days. There are two main groups: Flagellata, or Monads, provided with one or two flagella, or long bristle - like cilia; and Ciliata, which are furnished with numerous vibratile cilia. Class IV.—Spongida. An ordinary Sponge is a compound animal, or, more properly, an aggregated colony of individual cells, sup- ported on a skeleton of horny fibres, which are so united as to form a net-work of tubes. The essential part is the glairy, gelatinous substance investing this elastic frame- work. It consists of myriads of mouthless, sarcode bodies, which in some respects resemble Amoebse, but approach d h. Fio. 134.—Hypothetical Section of a Sponge: rt, superficial layer; &, inhalent pores; c, ciliated chambers; d, exhalent aperture, or osculum; e, deeper substance of the Sponge. the flagellate Infusoria in being uniciliated, and the Ily- drozoa in having two layers of cells in the body-wall, and in producing true eggs. While in other Protozoa aggre- gation is a result of growth, and the parts are not mutual- ly dependent, in Sponges the parts work for the life of the whole, giving the mass a kind of individuality, Differeu-. 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 Orton, James, 1830-1877. New York, Harper and brothers
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
