Shell minute, glassy white, slender, acute, with a four-whorled brown nucleus in which the nepionic part is prominently peripherally keeled and the axial lines of the reticulum are prominent; the whole is followed by two or more translucent whorls on which the keels gradually disappear; suture distinct, not appressed; anal sulcus shallow, the fasciole indistinct; spiral sculpture of faint sparse spiral striae only visible under magnification; axial sculpture practically none; last whorl evenly rounded, with a long twisted, straight pillar, with a minutely pervious axis; aperture narrow, outer lip thin and sharp. Length, 4.6; diameter, 1.3 mm. U. S. Nat. Mus. Cat. No. 107050.
One specimen off Fernandina.

The holotype is probably full grown, while the other specimens seen are young. The type also lacks the larval shell, and we are therefore not completely certain about the identity of our material. The similarities in sculpture and form, however, are so great that we do not hesitate to use Watson's name.
This species resembles F. catharinae considerably but that species has stronger spiral sculpture and more distant axial ribs on the larval shell.