It depends on the species, but many of them do grow straight down.
so does this mean the deeper the pot the better right?
looks like were waiting to find out
They grow in a ball, but it really varies species to species. Amp and Bical roots are massive and completely different than what you can expect from an Alata or Maxima but they're the same consistency.
Courtesy of Sunbelle
They're rather delicate and think of them as sewing thread and not wires like on other plants.
Timmy, if you're considering buying an Ampullaria, please reconsider. Them bad boys' don't take kindly to any cultivation errors. They're very expensive, require a fair mount of heat/humidity, and you would be much happier with a highlander based on what you tell us about your conditions.
I think they're awesome and beautiful plants and I understand the charm as well, but they're very expensive to keep and critically more difficult than your average plant.
Start a thread on nep suggestions! We'd be glad to help man.