Crossea biconica is a species of small sea snail or micromollusc, a marine gastropod mollusc in the family Conradiidae.

Sculpture : The first and second whorls are smooth, the third comparatively coarsely cancellated, the fourth contains dense fine spiral cords crossed by fainter growth lines which tend to bead the interstices.

The wide and deep umbilicus is bordered by a conspicuous ridge, and has an elevated funicle winding within.

The oblique aperture is rhomboidal, channelled by the umbilical ridge, and with a gutter at the termination of the funicle.

The small size, produced base, and wide umbilicus are characters which distinguish this from other Australian members of the genus.