The length of the shell attains 1.1 mm, its diameter 0.9 mm. (Original description) The shell has the habit of a minute
Stenothyra W. H. Benson, 1856; the outer
lip is not contracted, but the columellar lip um in adults travels forward to meet it, leaving a chamber behind. The nucleus is cancellated, and the base is bluntly ribbed. (Described as
Amphithalamus stephensae) The shell is minute and pale brown with an ashy tinge, except for the columellar region, which is flesh-colored. When the animal is present, the early
whorls appear much duskier. The nuclear whorls number 1.5; the first half is smooth, while the rest are marked by rather distantly spaced, poorly developed, rather broad spiral lirations, of which nine are present between the summit and the periphery. In addition to this, inconspicuous lines of growth are visible. Post-nuclear whorls and
sculpture: The post-nuclear whorls are strongly rounded and narrowly shouldered at the summit, with the portion appressed to the preceding whorl appearing as a band through the substance of the shell. The periphery features a weak keel that is truncated rather abruptly posteriorly but grades gently into the substance of the shell toward the base. The suture is well marked. The base is short, inflated, strongly rounded, and marked by lines of growth only. A heavy
callus is present at the insertion of the
columella, which at its posterior termination almost forms a cord. The columella itself is very heavy and oblique. Aperture and operculum: The conformation of the aperture is characteristically Amphithalmid; that is, the
aperture, which is oval, is much contracted by a shelf extending out from the columellar and parietal wall toward the outer lip, thus contracting the aperture. This shelf forms a decided pit behind its edge. The inner and parietal lip of the aperture, therefore, are not in contact with the columellar or parietal wall, but are at some distance from it. The posterior portion of the outer lip, however, extends upward to the preceding turn, which it joins immediately below the peripheral keel, as in mollusks with a normal aperture. The
operculum is thin and paucispiral. ==Distribution==