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Stylatractus santaeannae (Campbell and Clark, 1944)

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Shell large, egg-shaped, with two strong, opposite, equal polar spines (our specimen tipped up), spines shorter than vertical axis of shell (ratio of 1:1.4). strongly conical (7°) in side view, very thick (0.2 its own length at base) swordlike in proximal 0.67, with there equal, equidistant, slightly sinuous, peripherally thick (decurrent, thickest at base) blades, latter part circular in section, tip sharp, and base with blades seperated merged on shell surface; cortical shell elliptical (its minor axis 0.86 major axis) and regulary contoured; medullary shell large (at least half cortical shell) similary shaped and contoured; radial supports two very thick polar rods, four transverse and radial bars thinner than polar; pores of cortical shell large, subcircular, deeply set into deep framework wich has short, blunted sepaloid points, subuniform in size, and of similar form, about eight or nine in vertical axis, fewer in transverse axis, pores of medullary shell subhexagonal, smaller than those of cortical shell, shallow, framework less heavy than cortical framework. Length, total, 340 µ, of cortical pores, 19.8 µ, of medullary pores, 13.2 µ.
Lithatractus santaenae n. sp. is a heavy-set, strong species unlike other of genus.
(Campbell and Clark) 1944











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