Unknown invert in saltmarsh area

Unknown invert in saltmarsh area

Observation - Unknown invert in saltmarsh area. Description: Saw this critter running in a saltmarsh area, quite big, I would estimate at least 1 inch in length. Hope someone can help out, thanks.

Saw this critter running in a saltmarsh area, quite big, I would estimate at least 1 inch in length. Hope someone can help out, thanks.