^O. ocellatus^ (Rathbun), ^Platyonichus ocellatus^ (Latreille), the lady-crab or sand-crab. A species common on sandy shores from Cape Cod to Florida. It is found among the loose sands at low-water mark, even on the most exposed beaches, and also is abundant on sandy bottoms offshore. At low-water mark it buries itself up to the eyes and antennæ in the sand, where it watches for prey and foes, and quickly disappears beneath the sand when danger approaches. It possesses the power of burrowing in common with other marine animals which inhabit exposed beaches of loose sand. By burying itself deep in the sand it is protected from the action of the breakers. This species is easily distinguished by the color and shape of its carapace, taken in connection with its posterior swimming-feet. The body is nearly as long as it is broad, with five prominent spines on each side. The front margin is indented on each side of a three-spined rostrum, to form cavities for the eyes. The first limbs are large and have claws; the posterior ones are flattened into swimming-feet, and the intermediate three pairs are simple in structure, ending in points. In color it is white, covered with spotted rings of red and purple. [pg277] WALKING CRABS FAMILY ~CANCROIDÆ~ GENUS ^Cancer^ [Illustration: /Cancer irroratus/, the rock-crab; male.] ^C. irroratus^, the rock-crab. This is the common crab of the New England coast. It ranges from Labrador to South Carolina, but is rare south of New Jersey. It is found on sandy as well as on rocky shores at and below low-water mark and also between tide-marks, hiding among rocks, nearly buried in sand or gravel, and in tide-pools, where sometimes amusing combats between the males may be seen. The carapace is suboval, one third broader than long, the breadth being often from three to four inches. The surface is granulated but smooth; the color is yellowish, closely dotted with brown. The eyes are on short stalks in deep, circular holes, and between the eyes are small teeth. There are nine blunt teeth along each side of the front edge of the carapace. The first pair of legs are short and stout, and terminate in claws. The four posterior pairs are slender and end in pointed tips. This is an edible crab, and it is devoured by the larger fishes, but does not—although there seems to be no reason for it—share to any extent a place in the markets with the blue crab, /Callinectes sapidus/. [Illustration: /Cancer borealis/, the Jonah crab; male.]