THE JOINTED-FOOT ANIMALS 145 



slender, stilt-like appearance of its legs. Having no means of 

 aggressive defense, it relies almost wholly on the fact that its 

 color is very much like its surroundings. The cephalothorax 

 is covered with coarse, hair-like, flexible spines, and the gen- 

 eral color is dull gray. Frequently we find on the back 

 small seaweeds, hydroids (p. 265), sea-anemones (p. 252), and 

 even rock-barnacles (p. 151), growing as they would on rock. 

 This protective resemblance appears to be very successful 

 from the point of view of the spider-crab, for they are in some 

 regions more abundant than any other kind of crab. In some 

 parts of Long Island Sound the spider-crabs are so numerous 

 that they get into the " lobster-pots " set by fishermen and 

 crowd them so that no inducement remains for the lobsters 

 to enter, much to the disgust of the fishermen. Along the 

 Atlantic coast this species grows to have chelipeds which 

 extend over one foot from tip to tip. The giant Japanese 

 spider-crab has chelipeds which extend over fifteen feet from 

 tip to tip, and has a body correspondingly large. 



The edible crab, more frequently called by naturalists the 

 blue crab (Callinec'tes sap'idus, Fig. 71), is characterized by 

 having sharp lateral spines of large size, and by the last pair 

 of thoracic appendages being flattened and adapted to swim- 

 ming. The chelipeds are strong and fitted for cutting ; the 

 succeeding three pairs of appendages have no nippers, but 

 come to a point. 



As is well known, the blue crab is caught in large num- 

 bers along the Atlantic and Gulf coasts for the markets in 

 the cities. The industry is of considerable value commer- 

 cially, and for that reason very general attention has been 

 given to the distribution and habits of this crab. They are 

 caught most easily soon after the molting, which takes place 

 in early summer, and are then called soft-shell crabs. It is 

 at this time also that they are considered most valuable as 

 food. 



