The length of the white shell attains 8.5 mm, its diameter 3 mm. (Original description in Latin of
Vexillum castum) The white shell is rather thin and has an elongated, spindle-like shape. It is sculpted with curved, lengthwise folds, and the spaces between these folds are grooved crosswise. The
spire is elongated and consists of ten scarcely convex
whorls that are slightly knobby near the top. The
body whorl abruptly narrows toward the front. The
columella has three folds, the
siphonal canal is slightly extended and curved backward, and the outer
lip is sharp and simple. ==Distribution==