Placosema Opik 1967 Genevievella is a genus of trilobites with a short inverted egg-shaped outline, a wide headshield, small eyes, and long genal spines.

The backrim of the headshield is inflated and overhangs the first of the 9 thorax segments.

The 8th thorax segment from the front bears a backward directed spine that reaches beyond the back end of the exoskeleton.

It has an almost oval tailshield with 5 pairs of pleural furrows.

It lived during the Upper Cambrian in what are today Canada and the United States.