I've got them as well.........I forget the species that I would up getting from researching them........but they are fine.
They look to be the same......and if in fact they are....you need not worry.......since you don't have a positive ID......just keep an eye on them and see how they fare...
Can you do a bit more in depth as to what they look like...color? shape? Dwell in sand or rock? Do they contract into themselves like rolling a sock? Are they anchored in one spot?