Amphisorus Ehrenberg 1839

Test large, discoidal, biconcave with thickened rims, megalospheric proloculus and flexostyle of a half whorl followed by a large deuteroloculus that has numerous apertures, later chambers cyclic and subdivided by septula, microspheric peneropline early stage with about six undivided chambers and up to ten additional spiral chambers with septula before becoming annular, septula alternating and forming lateral chamberlets, leaving a large annular passage in the median plane that is not crossed by the lateral septula, a system of crosswise oblique stolons connects successive chambers; wall calcareous, imperforate, porcelaneous; aperture of numerous pores on the peripheral margin, elongated across the margin, and aligned in two alternating rows, additional supplementary openings in the median plane in the megalospheric test open into the median annular passage, microspheric test may have more elongate and more irregular openings into the annular passage. Miocene to Holocene; Indian, Pacific and Atlantic Oceans, Caribbean. (Loeblich & Tappan, 1987, Foraminiferal Genera and Their Classification)