This fountain is very beautiful, with two octagonal basins, one internal, and the other external. One finds it in the Val di Montone, facing the Porta Tufi. The interior of the fountain is completely decorated with little shells of many shapes and colors. A niche stands over the principal basin; at one time it probably contained a sacred image or statue, but now it is empty. Near this fountain is also a bottino that appears to lead toward the Porta San Marco.