Shell small, polished, grayish white, with transverse narrow streaks of very pale brown, five-whorled, with radiating grooves and wrinkles in front of the suture as in N. livida. Apex acute, nucleus rather large, lucid; whorls very round, flattish in front of the suture, which, near the aperture only, is a little appressed. Surface pretty well covered with very fine spiral markings, too fine and faint to be called striae. Aperture semilunar, with a thick white callus on the body. Umbilical opening bearing about the same proportion to the size of the shell as in N. intricata, but the respective components dissimilar; in N. intricata the margin of the umbilicus is bounded by a rounded rib, sepa¬rated from another similar rib above by a deep channel. Above these two is a wider and deeper furrow, above which is the larger umbilical rib, which lies very close to the preceding whorl. In N. nubila the umbilicus is bordered by a sharp groove, within which is a broad nearly flat band corresponding to the two lower ribs of intricata, above which are the larger furrow and rib, which last is not so close to the preceding whorl as in intricata. The umbilical region is entirely white. The operculum has not been seen, but is doubtless horny. Max. alt. of shell, 13.0 mm; of aperture, 9.0 mm; max. lat. of shell, 12.3 mm.

Shell with four and a half convex whorls which are slightly concave below the suture, with strong growth lines which are somewhat plicate above, but are smoother below; it is also sculptured with exceedingly faint spiral lines; aperture semilunar; columella straight; umbilicus moderately open, surrounded by a revolving ridge at its base, which projects within, partly closing it. Color dirty milky white, faintly clouded with brownish.
Height, 10; diameter, 10 mm.
Mayaguez, Porto Rico; two slightly worn shells; also Barbados and the Gulf of Mexico.

In one of the specimens the cloudy brown color was diffused, and most evident above the periphery. In the other it was more in the form of faint transverse streaks. The shell is especially different from N. intricata in its turrited spire and rounded whorls with radiating grooves above, and in the peculiarities of the umbilical region below.

Gulf of Mexico. Also near Barbados.