SIGMOILINELLA S. Y. Zheng, 1979

 

 

Type species: Sigmoilinella tortuosa S. Y. Zheng, 1979; OD.Sigmoilinella S. Y. Zheng. 1979 (*3449), p. 130. 208.Test elongate fusiform, twisted in appearance. subtriangular in section, chambers one-half coil in length, with planes of coiling changing to give a sigmoiline appearance in section, later chambers added in a single plane. three to four visible from each side, cham­bers with floors, widest at the base and tapering through the middle and later part, terminally produced as a long neck; wall calcareous, imperforate, porcelaneous, surface smooth. or with a few low longitudinal costae; aperture rounded, at the end of the produced neck, bordered by a distinctly thickened rim, and with a short bifid tooth. Holocene; China: Xisha Islands.