Mud crabs often turn up in dredge tows from Vineyard sound. They are often found within the crevices and hollows of sponges and encrusted shells and are a common piling crab. They are a relatively small crab with powerful claws.

Mud crabs can be recognized by their small size and robust claws with black "fingers." Mud crabs are a significant predator on small bivalves such as clams and oysters.

Barnes, R.D., Invertebrate Zoology, 1980, Saunders College and Holt, Rinehart and Winston.