Mikadotrochus beyrichii, common name Beyrich's slit shell, is a species of sea snail, a marine gastropod mollusk in the family Pleurotomariidae.

[2] It was discovered by Franz Martin Hilgendorf in an ancient Japanese collection.

It is pale yellow, beautifully flamed with 11 red whorls that are regularly increasing.

These lirae are beset with weak nodules, about 3 times as long (in the direction of the spiral) as high or broad.

This base contains 20 concentric lirae, and in the middle a deep pit or "false umbilicus".