I saw this crab near the pier at Fredericksted St Croix in less than 20 ft of water.

I am not suggesting it is something unusual.  I just do not see a good match in the book I have for an ID.

 

Crab

 

 

 

Hi Dave

 

I get nothing when clicking on the link. May be better to upload a copy of the image to your post?

TimG,  Than you for the suggestion.

 

Diver Dave

 

Could it be a Hairy Clinging Crab? 

That could be it!  I have no better suggestions based on the one book I have. My book says that crab is 2-4 inches.  i thought it was a bit bigger than that but it is difficult to tell as it was tucked into a spot that prevented getting too close.

It is a very cool looking crab!

It sure does look like a Hairy Clinging Crab, Mithrax pilosus.