Cyclostremella humilis Bush, 1897
Distribution: North Carolina, Florida, Texas; Mexico. Size: 2 mm
Description: Color translucent white; shape planispiral; sculpture of crowded, sigmoid, radial lines with microscopic spiral threads, spirals most prominent on periphery of shell; tilted sutures form a channel; protoconch heterostrophic; umbilicus deep and broad; aperture subcircular; operculum spiraled. Habitat: Probably a surf-zone inhabitant. Depth range 0 to 29 m (95 ft). Remarks: Bush (1897) first placed C. humilis in the family Vitrinellidae. Moore (1966) placed it in the family Cyclostremellidae, and Robertson (1973) placed it in the family Pyramidellidae because of morphological and anatomical features, with emphasis on the heterostrophic protoconch. Is a common beach-drift species all along the Texas coast. See Ode (1968g); Ode and Speers (1970i); Andrews (1977).