Iridescent swimming crab

The small Iridescent swimming crab, Portunus
gibbesi, is found from Massachusetts to the Gulf.
It is a relative of the blue crab.
(I just noticed that there appears to be button-like eyes on the back side of the main shell. The real eyes are on the claw-side/mouth-side. I'll have to do a bit more research on crab eyes. -ed)
(Photo by Dave Bulloch)