Kofoid tabulation system

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The tabulation system developed by Kofoid (1907b,c, 1909, 1911a) and employing four landmarks: the sulcus, the cingulum, the apex (usually determined by the apical pore complex), and the antapex. The plates immediately anterior to the cingulum constitute the precingular series; the plates immediately posterior to the cingulum constitute the postcingular series; the plates contacting the apical pore complex make up the apical series; and the plates in the region of the antapex constitute the antapical series. Plates occurring between the precingular and apical series and between the postcingular and antapical series are termed anterior intercalary plates and posterior intercalary plates respectively. Plates in the cingulum constitute the cingular series and those in the sulcus are sulcal plates. In the Kofoid tabulation system the individual plates in each series (except the sulcals) are numbered consecutively, starting with the plate closest to the midventral position and circling the cell parallel to the transverse flagellum - i.e. anticlockwise in apical view and proximal to distal in respect to the flagellum itself. Kofoid (1909) used a superscript notation to designate each series in conjunction with the number of the plate in question. This has been variously modified over the years, and the following symbols are used herein: apicals ('), anterior intercalaries (a), precingulars (), cingulars (c), postcingulars (), posterior intercalaries (p), antapicals (') and sulcals (s). The following abbreviations are used herein to designate specific sulcal plates: anterior sulcal plate (as), right accessory sulcal plate (ras), right sulcal plate (rs), left sulcal plate (ls) and posterior sulcal plate (ps). Neontologists generally use the designations Sa, Sra, Sd, Ss and Sp respectively for these sulcal plates. The transitional plate on the left side of the sulcus in many peridinialeans is designated as "t". Plate sutures are designated by the labels for each of the two adjacent plates separated by a slash: thus, for example, 6/1' designates the suture between the sixth precingular plate and the first apical plate. Refer to Text-Figures 13-14.