4 g A NATURAL HISTORY OF THE SEAS 



■/chts. It has been dredged in deep water from the 

 . Vest coast of Ireland and Scotland. 



The members of the group known as Sand Crabs may 

 be distinguished by the triangular shape of the mouth 

 area, which is so arranged that the channels carrying the 

 outward stream of water from the gills are produced 

 forwards to the front of the head, so that breathing is 

 facilitated as the creature lies concealed in the sand. 



The Bashful Crabs (Calappa) are so called from the 

 huge leaf-like form of the pincers, which are held so as to 

 completely hide the countenance. This provision, how- 

 ever, is less the outcome of shyness than of the necessity 

 to keep the sand from entering the mouth and breathing 

 channels. Moreover, the crab when thus folded upon 

 itself presents such a compact and rounded formation 

 that it can be rolled upon the sea floor in a ground swell 

 without suffering the slightest inconvenience. 



In the Spider Crabs, which rank among the most re- 

 markable of all crustaceans, the carapace is roughly 

 triangular and the limbs are prolonged, often to a most 

 grotesque degree. Despite this length of limb the animals 

 are lethargic to a degree, and rely for safety almost entirely 

 on their genius for " camouflage." 



In some forms, such as the Arrow Crab (Leptopodia), 

 the creature is so coloured as to closely resemble weed 

 or coralline thickets, and as a result finds outside aids to 

 disguise superfluous. 



Many other Spider Crabs, however, have been forced to 

 excel in the art of dressing up whereby to evade their 

 many foes, and some striking examples are common around 

 all our native shores. The little Macropodia for example 



