. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. nZLIOZOA. 187 1. Impevforata. With membranous or calcareous shell, which is without fine pores, but possesses, in one place, an opening, either simple or sieve-liJce, through which the pseudopodia project. To these belong the Gromidce, with a mem- branous chitinous shell : Gromia oviformis Duj,, and MiliolidcP, with a porcellanous shell : Cormi^inraplanorlis M. Sch., Miliola cyclostoma M. Sch., from the Miliolite chalk. 2. Perforata. The shell, which is usually calcareous, is invariably pierced with
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. nZLIOZOA. 187 1. Impevforata. With membranous or calcareous shell, which is without fine pores, but possesses, in one place, an opening, either simple or sieve-liJce, through which the pseudopodia project. To these belong the Gromidce, with a mem- branous chitinous shell : Gromia oviformis Duj,, and MiliolidcP, with a porcellanous shell : Cormi^inraplanorlis M. Sch., Miliola cyclostoma M. Sch., from the Miliolite chalk. 2. Perforata. The shell, which is usually calcareous, is invariably pierced with innumerable fine pores as well as by one larger opening, and has complicated passages in the partition walls of its chambers. The Lagenidce have a hard shell, with a large opening surrounded by a toothed lip : Lacjcna vulgaris Williamson. The GlohigerinidcB on the contrary have a hyaline shell pierced by large pores, and a simple slit-like open- ing : Orbulina universa D'Orb., Globigerina bulloides D'Orb., Rotalia D'Orb., Textularia D'Orb. The greatest size is attained by the Mimmulhiidep, which possess a firm shell and an in- ternal skeleton, which last is pierced by a complicated canal system : Polystomella Lam., Nummulina D' Order 2.—Heliozoa.^' Fresh-water Rhizo2Jocls usually with pulsating vacu- ole, and one or more nuclei. A radial silicious skeleton sometimes pi'esent. The sarcode body sends out in all directions tough radiating pseudopodia (fig. 128), When a skeleton is secreted, it consists either of radially arranged silicious spines [Acanthocystis) or of latticed silicious shells {Clathrulina), and so closely resembles the skeleton of the Radiolaria that the Heliozoa have been actually described ^s fresh-water Radlolaria. They differ from the Radiolaria in the absence of the complicated FiO. 128.—Young Actin single nucleus (af tei F. '. :phiE}-ium, still with a , Schultze). iV, Nucleus. * L. Cienkowski, " Ueber ; Areliiv. fur mikrosk.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
