Xanthodaphne pachia is a species of sea snail, a marine gastropod mollusk in the family Raphitomidae.

Spirals: the whole surface is sparsely scored with very shallow, scratched-out, narrow furrows, parted by flat intervals of from two to six times their breadth.

On the snout they gradually broaden till their intervals assume the form of slight rounded threads.

Its edge forms a very regular curve with a slight shoulder above, between which and the body lies the broad, shallow, rounded sinus.

The inner lip is a thin narrow glaze which very soon dies out on the oblique, twisted, fine edge of the short conical columella, beyond whose point the front of the shell advances a good deal.