Walking Shrimp

As with the swimming shrimp, we have been unable to classify these walking shrimp. We find them on both sand and mud bottom and are not sure they are shrimp at all. They certainly are crustaceans. If anyone knows what these actually are please let us know.	Walking Shrimp
At first glance it appears one of the walking shrimp that came out of a hole in the mud picked up a small disk-like object with one of its feet. On closer inspection we think that the small disk-like object grabbed the leg of the shrimp. The shrimp sort of backs away shaking its leg.	Walking Shrimp Caught by Thing