Spirotropis cymothoe is a species of sea snail, a marine gastropod mollusk in the family Drilliidae.
The length of the (decollated) shell attains 9 mm, its diameter 5 mm.
(Original description) The shell much resembles Cryptogemma calypso <small>Dall, 1919</small>, from which it differs by having the anal fasciole striated spirally, the surface in front of the shoulder without spiral sculpture and minutely vermiculate, the ribs more knob-like, shorter, and averaging about 12 on the body whorl. The shell contains 6 whorls. The apex is always eroded.
This marine species occurs in the Pacific Ocean off San Diego, Lower California at a depth of 650 m.