shore crab

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various crabs found along seashores, especially Carcinus maenas, native to Europe and widespread elsewhere.

from The Century Dictionary.

• noun A littoral crab of the family Carcinidæ; specifically, Carcinus mænas. See cuts under Brachyura, Carcinus, Megalops, and Zoæa.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A type of crab (Carcinus maenas) native to the coasts of Europe and North Africa.