Located on the south side of the atrium was an arched niche 1.35m above ground. The interior of the niche was plastered with its base being constructed from bricks. Above the niche was a painted cylindrical altar (or tripod according to Fiorelli), upon which the Genius pours a libation. Beside the Genius stood the tibicen and a Lar. Below the niche were two serpents with an altar furnished with offerings. On either side of the niche were large paintings of dogs. The left dog appeared to be lying down while the right appeared to have its mouth open barking. The upper arms of a man could be seen extending behind this second dog. None of the painted scenes survives today.