Protoconch: smooth, globular, strongly hypertrophic, at about 130 degree angle to teleoconch axis; embryonic whorl fully or largely exposed; consisting of about 2 12 whorls; PD 540-600 µm; with weak peritreme. Protoconch umbilicus completely covered by callus, exten¬ding between first TW and anal keel. Glassy or milk-white; embryonic whorl, protoconch suture and callus tan.
Teleoconch: slender cone-shaped; 4.3-5.7 mm at 5 to 6 + whorls; spire angle 31-32degrees. Pattern of regular spiral and weaker axial ribs, intersecting at almost right angles to form strong nodules. Spacing of the axials very regular, with ca. 17-21 on fourth whorl. Exposed upper part of whorls with 3 spiral ribs (middle one weakest, lowermost strongest); large specimens with weak additional thread below the middle rib. beginning at about 5,75* TW, upper point of whorl attachment at a recessed, fifth spiral rib, partly covering it. On body whorl, this rib, and one of almost equal strength immediately below it, forming double keel at outer base. Basal area with 4-6 indistinct spiral threads. No open umbilicus; callous columella, relatively thick-shelled in larger specimens. Coloration: Early whorls white; after about 3 TW spiral ribs, especially first and third, with tan color, darkest between nodes. Animal: unknown.

This species can be recognized by its pattern of three nodose spiral ribs on the exposed part of the teleoconch whorls, combined with distinct coloration. A similar form in the study area is Mathilda brevicula , which differs by its open umbilicus and greater degree of heterostrophy. In the latter, the embryonic protoconch whorl is never exposed on the shell apex. A similarly three-ribbed form is Mathilda retusa Brugnone, 1873. described from the Mediterranean Sea. In that form, the second and third primary spiral ribs are of equal strength.