Acrilla affinis is an extinct species of sea snail, a marine gastropod mollusk in the family Epitoniidae, the wentletraps.

[1] (Original description in French) This is an elongated, turriculated, narrow shell, with fifteen to sixteen convex whorls, joined by a fairly deep but not canaliculated suture.

The surface is decorated with a large number of longitudinal, thin, equal and regular ribs.

They are straight for the greater part of their length, but reaching the vicinity of the suture, their lower end bends sharply, forming a small auricle.

The rather narrow interstices of the ribs show under the magnifying glass very fine transverse striations, obsolete, but of admirable regularity.