[jshepherd]

True, they are all referring to a type of South Sea pearl from the genus Pinctada, but the different varieties come from differing species with hinge teeth - Pinctada margaritifera, Pinctada maxima, and Pinctada mazatlanica (I may be missing one). You are probably dealing with a resale Site, not a producer of the strands. I guess it is also possible that the person who answered your question may not really know, they could be an employee with short experience. The mollusk that produces the Tahitian pearl is not the white lip - that answer is wrong.

If the pearls are dirt cheap on eBay (round Tahitians), they are not real, or they are total garbage. There is no way to get a decent round strand of Tahitians in an acceptable quality for anything less than the $2000 range - that is production cost. For a good to fine quality production is closer to $3k.