Compsodrillia eucosmia is a species of sea snail, a marine gastropod mollusc in the family Pseudomelatomidae, the turrids and allies.

The fasciole is rather wide, excavated, undulating in harmony with the ribs, marked by fine revolving threads and marginated at the appressed suture by a stout elevated line.

The transverse sculpture consists of (on the penultimate whorl 9) stout, rounded ribs, beginning at the fasciole and obsolete on the siphonal canal.

The brown touches are on these ribs above and below the white zone, which is bounded by the peripheral pair of primary spirals.

A single internal thread runs parallel with the fasciole deeper in the throat.