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Theocyrtis diabolensis Clark and Campbell, 1942

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Shell small, apically strongly pointed and with two swollen, ringlike segment below the conical cephalis; apical horn much reduced as a mere equally four-angled, sharp point; cephalis acuminate (40°), its length less than 0.22 total length, the apex narrowly rounded over, the sides neraly plane, mostly symmetrical, the basal diameter nearly 1.2 times the height, with very little change in contour between it and the thorax; thorax conical-ring shaped (16°) ,about 0.27 total length, the basal diameter 1.5 times the diameter at the base of the cephalis, the sides strongly bulged, much resembling a wide, old-fashioned wedding ring; the bulge at the middle equals the basal diameter, the base, however, very sharply constricted at the internal, septal ring which marks off its lower margin from the abdomen; abdomen similar to thorax in general shape, its middle being only a trifle wider than the thoracic bulge, the apertural end, however having a diameter of 0.28 total length; aperture margin torn, possibly irregular, not toothed; wall fairly thick, outwardly smooth, as a whole neatly trim; surface of horn, hyaline; of cephalis hyaline with only a very few, tiny, circular pores near the upper part; of thorax, with about sixty, subequal, double-contoured, circular, very well-spaced pores; of abdomen with about the same number of pores as the thorax or, perhaps, a few less, these pores larger than those of thorax but otherwise similar, the pores of both thorax and abdomen tending to be mildly spiralled (about 5°) in subregular tiers; framework, drak, grey, dense. Length of shell, 145µ; diameter of base of cephalis, 38.6µ; of septal ring , 60.6µ; of pores, 2.2-6.6µ.
Clark and Campbell 1942











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