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Phormocyrtis proxima Clark and Campbell, 1942

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Shell smooth, with the maximum diameter well up on the thorax, as a whole little swollen and with slight (or no) apertual contraction, surface strongly ribbed; apical horn rather short, more like a spike than a distinct horn (its length sometimes only about 0.5 length of cephalis), conical in outline, mostly thin but sometimes stout, equally four-bladed, with four fins, the tip sharp, basally merged to the top of the cephalis; cephalis conical (70° decreased to 20° in the basal 0,5), The top caplike, the sides spreading, the base chiefly distinguished by sudden change in lateral shell contour and its junction with the thorax, its sides not markedly convex, often distinctly asymmetrical, the blades of the horn continued down the sides nearly to the base; thorax with narrowly rounded (73°) shoulder reaching a maximum diameter of 0.15 graeter than the length of the thorax itself near the middle, thence gradually contracting (30°) or sometimes continued in the lower thorax as a cylinder, the lower margin of the thorax itself, this lower level marked by an internal, horizontal, narrow, septal band; abdomen inverted truncate-conical in its upper potion, thence subcylindrical with slightly concave sides, and with an undulant, truncate, circulate margin whose diameter is nearly 0.5 the maximum diameter of the thorax; wall uniform, trim, and rather thick; general surface and pore characters almost exactly as in the related species linguata n.sp., in the lower stratigraphic horizon. Length of the shell, 190µ (tipped); of horn, 21.0µ; of cephalis, 25.4µ; of thorax 80.4µ; diameter of maximum, 91.4µ; of aperture, 51.8µ; of thoracic pores, 4.4µ.
Clark and Campbell 1942











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