Early Miocene; Extinct.
Original Description (from Maury, 1910, p. 21):
"Shell tapering regularly to an acute apex; whorls eight in mature shells, the two nuclear being smooth, the subsequent whorls bearing each about twenty very regular, straight transverse ribs, extending the full length of the whorls; beneath the suture the ribs are cut by an incised spiral line so that their ends appear as a series of beads crowning the summit of each whorl; lower half of the body-whorl with about six spirals which become obsolete above the center of the whorl; aged shells have the outer lip lirate within and the callus of the columella plicate. Height of shell 13; of aperture 5; greatest width 5.5 mm.
The striking features of this unusually beautiful Nassa are the regular and elegant riblets and the absence of spirals except just beneath the suture and on the base of the body-whorl.
Oligocene of the Chipola marls, Bailey's Ferry, Calhoun County, Florida and of the Oak Grove sands of Santa Rose County, Florida.Named in honor of Dr. Bertha Stoneman of the University of South Africa.
Cornell University and Mr. Aldrich's collection."
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