what crab ?

ID please, this was seen in Monterey, about the size of a quarter coin.

http://www.flickr.com/photos/cadiver/4511457881/

Thanks!

Looks like the California elbow crab Heterocrypta occidentalis. They may be more common in soft bottom areas since an alternative common name is the sandflat elbow crab. Monterey is about as far north as they get.