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Stylacontarium bispiculum Popofsky, 1912

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Cortical shell ellipsoidal (ratio of polar to equatorial axes about 1.09-1.12), tick.walled, thorny, with 10-12 circular to subcircular pores of equal dimensions on a half-equator. Polar spines conical of variable length, generally shorter than the polar axis of the cortical shell. Outer medullary shell spherical or ellipsoidal with polygonal pores framed by very thin bars, connected to the cortical shell by two bars collinear with the polar spines, and by 6-8 bars in the equatorial plane. Inner medullary shell a loose meshwork.
Measurements based on 30 specimens from Samples 266-13,CC; 266-15,CC; abd 266-13-1,51-53: length of the polr spines, 45µ-72µ; of the polar axis, 135µ-180µ; and of the equatorial axis, 126µ-171µ; maximum diameter of the outer medullary shell, 36µ-45µ.











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