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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.
