title: Some critical qualitative details of lorica construction in the type species of Calliacantha Leadbeater (Choanoflagellata).
abstract: Qualitative structural details, amplifying or correcting previous accounts in the literature on this species have been compiled by means of light and/or electron microscopy of dry whole mounts, prepared in situ from freshly gathered wild material mainly from temperate sources in Denmark, Britain and south Alaska. The more important findings are summarized diagrammatically. These include elaborate and constant details of assembly at the anterior end of the lorica, combined with much greater variability at the hind end. The absence of continuity between the three anterior spines and any of the six longitudinal costae present at the front end of the lorica chamber is confirmed, but a range of conditions involving numerical reduction in costal numbers at the hind end is illustrated. The overall size range encountered in the three temperate localities listed is illustrated photographically, but the large cells characteristic of arctic sources are represented, for a qualitative purpose only, by means of a single photograph recording a specimen collected beneath sea ice in N. Alaska, a source which will be considered more fully on a later occasion.
mesh_terms: D000413:Alaska; D003718:Denmark; D004739:England; D056890:Eukaryota / Q000145:classification / Q000648:ultrastructure*; D012623:Seawater; D013045:Species Specificity; D014871:Water Microbiology