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Acanthoeca spectabilis Ellis, 1930. Cells are 3.5-5 microns in length, elongate with a pointed posterior, and fit closely to the main chamber of the lorica. Electron microscopy reveals that these cells are enclosed by fibrous material. The pseudopodial collar is shorter than the cell and the flagellum projects slightly from the top of the lorica. The main chamber of the lorica is conical and tapers posteriorly, giving rise to a pedicel. Costae in the main chamber give rise to longitudinal spines anteriorly. Fibres were present and arranged in the same pattern as costal strips in normal cells, except that, being less rigid, the spines are irregular and crumpled. The conical shape of the main chamber and the pedicel appears to be maintained by a membranous structure in the cells with a fibrous lorica.
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This image was made from samples taken during a scientific cruise in the Pacific. Water was filtered to concentrate the organisms that were present, then dried onto a thin sheet of plastic and then shadowed with a fine layer of metal to provide contrast. The preparation was then observed with an electron-microscope. This technique has been used to document the diversity of marine microbes, especially, protists in the oceans.
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This image was made from samples taken during a scientific cruise in the Pacific. Water was filtered to concentrate the organisms that were present, then dried onto a thin sheet of plastic and then shadowed with a fine layer of metal to provide contrast. The preparation was then observed with an electron-microscope. This technique has been used to document the diversity of marine microbes, especially, protists in the oceans.
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Crinolina isefiordensis Thomsen, 1981. Cell solitary, planktonic, living in skirt-shaped lorica, open anteriorly and posteriorly. Protoplast 8 microns long and 5 microns wide, without chloroplast. Single flagellum 2-3 times protoplast length, surrounded by a collar of tentacles. Height of collar approximately 6 microns, maximum diameter of collar 13 microns Lorica 25-30 microns long, diameter at base 20-30 microns, diameter at neck constriction 10-13 microns Longitudinal costae (12) 15-16, each composed of 6-7 costal strips. Two transverse costae. Longitudinal costae form spines at the anterior end of the lorica. Each spine is composed of two costal strips. Posteriorly the longitudinal costae project slightly beyond the transverse costal ring.
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This image was made from samples taken during a scientific cruise in the Pacific. Water was filtered to concentrate the organisms that were present, then dried onto a thin sheet of plastic and then shadowed with a fine layer of metal to provide contrast. The preparation was then observed with an electron-microscope. This technique has been used to document the diversity of marine microbes, especially, protists in the oceans.
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This image was made from samples taken during a scientific cruise in the Pacific. Water was filtered to concentrate the organisms that were present, then dried onto a thin sheet of plastic and then shadowed with a fine layer of metal to provide contrast. The preparation was then observed with an electron-microscope. This technique has been used to document the diversity of marine microbes, especially, protists in the oceans.
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Pleurasiga minima Throndsen, 1970. Lorica 9.5-16 microns long with 2 transverse costae and 7 longitudinal costae, all of which extend to the posterior of the lorica. The transverse costae are of about the same width, and the lorica narrows below the second costa to form a pointed base. Cell located at the posterior of the lorica, with flagellum protruding above it.
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Pleurasiga minima minima Throndsen, 1970. The different varieties differ mainly in size. The lorica of P. minima minima is about 10 microns long and wide.
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Pleurasiga reynoldsii Throndsen, 1970. The lorica is 23 microns long and 22 microns wide, respectively.
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Polyoeca dichotoma Kent, 1880. Lorica of polythecium urceolate, pedicellate, tapering posterioly, slightly constricted at a distance of one-third of the total length from the anterior margin, and then widening out to their greatest diameter, pediceles of each separate lorica straight, slender, varying from the same to two or three times the length of the latter structure, contained animalcules ovate, occupying respectively about one-half of the cavities of the lorica, contour of polythecium subdichotomous, each zooid usually giving rise by trasverse fission to two new ones which attach themselves to opposite sides of the parent lorica. Length of separate lorica 10 microns
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Portrait of the acanthoecid choanoflagellate, Polyoeca dichotoma (Kent, 1881). Cells are solitary or united to form linear or dendroid colonies which attach to the substrate. The lorica is funnel-shaped, constructed of numerous siliceous longitudinal costae, each made up of costal strips. The longitudinal costae terminate as anterior spines (11-17); 2 or more bands of equally spaced transverse costal strips (difficult to see in vivo) encircle the lorica chamber in which the protoplast (cell body) resides. At the apex of the funnel the longitudinal costae unite to form an aggregated pedicel. In dendroid colonies the pedicel of the daughter (anterior) cell attaches to the outside of the lorica of the parent cell. Details of lorica morphology are best seen with scanning electron microscopy. The cell body has one anterior flagellum (seen here) surrounded by a rhizopodial collar (not visible here). Division is nudiform (i.e. naked swarmers are formed which then form a lorica). Collected from a commercial saltwater aquarium in Boise, Idaho February 2004. DIC.
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Portrait of the acanthoecid choanoflagellate, Polyoeca dichotoma (Kent, 1881). Cells are solitary or united to form linear or dendroid colonies which attach to the substrate. The lorica is funnel-shaped, constructed of numerous siliceous longitudinal costae, each made up of costal strips. The longitudinal costae terminate as anterior spines (11-17); 2 or more bands of equally spaced transverse costal strips (difficult to see in vivo) encircle the lorica chamber in which the protoplast (cell body) resides. At the apex of the funnel the longitudinal costae unite to form an aggregated pedicel. In dendroid colonies the pedicel of the daughter (anterior) cell attaches to the outside of the lorica of the parent cell. Details of lorica morphology are best seen with scanning electron microscopy. The cell body has one anterior flagellum (seen here) surrounded by a rhizopodial collar (not visible here). Division is nudiform (i.e. naked swarmers are formed which then form a lorica). Collected from a commercial saltwater aquarium in Boise, Idaho February 2004. DIC.
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Savillea micropora (Norris, 1965) Leadbeater, 1975. Cells spherical to ovoid, with collar and flagellum. Cells located in base of lorica composed of longitudinal and transverse costae. Base of lorica with numerous closely spaced transverse costae, expanded anterior part of lorica composed of approximately 12 longitudinal costae traversed at regular or irregular intervals by 4-6 transverse costae. Terminal transverse costa forming pore with small diameter (approximately 1 microns diameter). Cell 2.5-3 microns diameter, base of lorica 1.6-3.5 microns long, 3 microns diameter, anterior part of lorica 5-6.3 microns long, 5-6.3 microns diameter.
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Savillea parva (Ellis, 1930) Loeblich III, 1967. Cells are 2.5-4 microns (spherical), lorica 10-10.5 microns in length. The cell body is situated at the bottom of the lorica, the pseudopodial collar extends about two-thirds of the way up the lorica, and the flagellum extends to the top of the lorica. Unlike Savillea micropora, a flagellum is always present and active.