You are right, when they made this they thought that Artemis' lumps were tatas and therefore a good idea to make this mysterious figure as a fountain :O)
Ah, @blue2mato, You're right, I've also seen something about bulls' balls. But when a figure has water streaming out of two dozen little muffins / headlights / bazoombas, I figure that somewhere, there must be a T-T.
Very interesting set! The round shapes on Artemis' torso are mostly considered to be bulls testicles. That corresponds well with her cult coming from the east, same as Magna Mater and Mithras, both being mystery cults with bull sacrifice at the center. This version of Artemis is from Villa d'Este, made in the rennaissance, so they mistook the forms as breasts (which correlated well with popular themes of Mary etc)