Something new in my tank...

[whaase]

I just noticed yesterday that I had all these round, white, spots on my glass. They are about 1/16" in diameter and very a bit in size. The only thing I have for livestock in my tank right now is cerith snails and blue legged hermits. The snails are always on the glass, always riding on each others back (not sure if that's normal or not). Any ideas what it could be?

Walter