Original description.
Shell acicular, uniformly yellowish wdiite. Early nuclear whorls decollated; the three remaining are marked by the characteristic sculpture, the double spiral thread, the posterior one of which is upon the middle of the whorls, and many slender, axial riblets, of which there are about twenty-four upon the last turn. Post-nuclear whorls increasing very regularly in size, ornamented with a double spiral row of strong tubercles. Channel separating these two rows quite wide. The tubercles are joined axially by low, rather broad riblets, which are decidedly protractive. Beginning with the sev- enth whorl the slender, median spiral thread makes its appearance. This is considerably nearer the posterior keel than the anterior, but in our specimens, which are all young, attains only a moderate development, with extremely weak tubercles. There are about eighteen ribs on the first, twenty upon the second, and twenty-two upon the penultimate post-nuclear turn. Periphery of the last whorl marked by a strong spiral keel. Base excavated without spiral keels covered by the feeble continuations of the axial riblets, which gradually fade out as they approach the short, stout slightly twisted columella. Aperture subquadrate, decidedly channeled anteriorly.