The Ephesian Artemis, the "great mother goddess" also mentioned in the New Testament (Acts, 19), was extremely popular in the ancient world, as we might deduce from the fact that copies of her cult statue have been excavated in many parts of the Roman Empire.
Although the statue as we know it was a substitute for the lost original, it retains several archaic traits (e.g., her static pose). Still, many aspects cannot be dated in the archaic age, and the statue from Lepcis that is next to this article illustrates this very well: on the upper part of her chest, she wears a zodiac, a symbol invented in fourth-century Babylonia. On other copies, Artemis wears a mural crown, a Mesopotamian and Syrian motif that became popular in the Hellenistic age. The winged Victories to the left and right appear to be innovations as well, although they have archaic antecedents.
On other copies, these elements are absent (e.g., instead of the Victories, we see lions), and they may be closer representations of the original. However, the fact that a statue with zodiac had been found in Ephesus, strongly suggests that the astrological aspect was not altogether absent from the Ephesian cult.
One of Artemis' characteristics is that she protects fertility. This may be symbolized by the spherical objects that cover the lower part of her chest, but the common assumption that they are female breasts is incorrect. They probably represent the testicles of a bull, although they may also be gourds, which were known in Asia as fertility symbols for centuries. Artemis' robe is always decorated with lions, leopards, goats, griffins, and bulls, which represent Artemis' title of Lady of the Animals.
Photos of the sad remains of the once splendid Temple of Artemis in Ephesus, can be found here.