<p>Douglas-<br>
You animal is a cave isopod. It is a true troglobite (loss of pigment and eye and is fully adapted for life in caves) and probably belongs to the genus <em>Asellus</em>. The critters feed on organic material washed into the cave or brought in by other animals living in the cave such as bats.<br>
To figure out the correct species would require keying out and some experience with using a key and microscope. You may be able to find more info on line but this can help you get started.<br>
Yes, it is related to Sow Bugs or Rolly Polly.<br>
Nice picture of an unusual critter most people don't get to see.</p>