paratively inconspicuous. When a female crab is 

 carrying her eggs attached to abdominal appendages, 

 she lowers the apron at intervals and uses it as a 

 scoop to drive water among the developing young. 



True crabs tend to run sidewise, "crab-wise," 

 rather than forward or back, although they can pro- 

 gress fairly rapidly in any direction. Often the body 

 is elongated transversely too. For crabs with this 

 body form, the name Cancer has come down from 

 ancient times. This is the type of crab for which the 

 zodiacal constellation is named, and the sign astrolo- 

 gers apply to those born in the month following June 

 22, when the sun enters this portion of the sky. 



Cancer crabs (Plate 96) are rock crabs, whose 

 hindmost pair of legs is fitted for running. In this re- 

 spect they differ markedly from the commercial blue 

 crab of America, Callinectes sapidiis, whose last pair 

 of legs end in flat, oval paddles. Callinectes is easy to 

 recognize because its body extends to each side into 

 a long, sharp spine. It is sold as the "hard-shell crab" 

 or held in a pen until it molts and is then put on the 

 market promptly as the "soft-shell crab." Actually, 

 any freshly molted arthropod has a soft shell. 



The blue crab is an active swimmer. So is its near 

 relative the green crab, Carcinides maenas, although 

 Carcinides' hindmost legs are merely flattened into 

 oars without losing their use in running (Plate 95). 

 Green crabs cause serious losses to shellfishermen by 

 eating young clams, oysters, and scallops. 



Far stranger in appearance is the common spider 

 crab Libinia, found on muddy bottoms along the 

 Atlantic coast of America. The spiny sac-shaped 

 body and long-segmented cylindrical legs suggest 

 either a spider or, because of the pale ivory color, a 

 creature composed of bare bones attached to a sort 

 of skull. The giant of all crustaceans is a Japanese 

 spider crab, Macrocheira kaempjeri, found in deeper 

 waters well offshore, where it achieves a reach of 1 1 

 feet from claw to claw. 



On many beaches, particularly in the tropics, 

 ghost crabs (Ocypoda. Plate 99) make their homes 

 well away from the water. Ocypoda, the "sharp- 

 footed one," has been described as the "rabbit of 

 the crustaceans," for it races over the beach away 

 from enemies. Its compact body may measure 2 

 inches across and 1 V2 from front to back, and the 

 legs straddle as much as 8 inches. 



When a ghost crab is ready to disappear down its 

 U-shaped or Y-shaped burrow in the sand, it lowers 

 its prominent eyestalks from their normal vertical 

 position into protective grooves along the front edge 

 of the carapace. In less temperate latitudes, toward 

 the extremes of their range, ghosts even hibernate in 

 the dunes back of the beach and show clearly how 

 independent of water they have become as adults. 

 Their gills, so necessary at younger stages, have prac- 

 tically disappeared, leaving empty chambers under 



Cave crayfishes are usually white, blind, and depend- 

 ent upon their especially long antennae. The body is 

 small and unpigmented, and the pincers as well as the 

 legs are unusually slender. (Missouri. Ralph Buchs- 

 baum) 



The spiny lobster Palinurus, lacking pincer-tipped 

 legs, depends on the whip action of its heavy anten- 

 nae for protection when it ventures from crevices 

 among rocks. ( France. Ralph Buchsbaum ) 



