New Snail

[snailrider]

Bought some live rock yesterday came with lots of tiny critters-even aiptasia and stars. But it is all good, as I also got a few new snails and a brittle star also. I didn't get a pick of the brittle star, the velvet damsel was picking on it when I saw it, then it dissapeared under the rock.

What kind of snail is this?