Football-shaped in cross section Two large claws Eyes mounted on stalks
The three very common True Crabs of Crane’s Beach may be found in one search of the tidal pools. They are:
Rock Crab (Cancer irroratus): A brick-red shell, somewhat granulated, with a black and yellowish undersurface.
Jonah Crab (Cancer borealis): Similar in color to the above, but its shell has a more sculptured surface.
Green Crab (Carcinides maenas): A greenish-colored shell. The last pair of legs end in sharp points, rather than being flattened like paddles.
Horseshoe Crab (Limulus polyphemus)
Shell with horseshoe-shaped outline Long, sharply pointed tail Two immovable compound eyes
The Horseshoe is not a Crab at all, but is more closely related to the spiders, mites, and scorpions. In spite of its relations, the Horseshoe is a harmless creature whose only protection is its hard shell. Therefore it may be examined freely—a strange “living fossil” that has survived 400,000,000 years of evolution with very little change.
The Mollusks
Oyster (Ostrea virginica)