138 CRAYFISH, LOBSTERS, SPIDERS, AND INSECTS 



Fig. 7li. — Crab, from a.lM>\-c. 



or a crayfish very little. The 

 covered by the carapace, is very 

 length (Fig. 76). The 

 abdomen, instead of 

 being long and large, 

 is short, and is pei'- 

 manently curled 1)0- 

 neath the head and 

 thorax. In this posi- 

 tion it is invisible from 

 above (Fig. 77). Both 

 pairs of aidenmc arc 

 ver3' small. The fii'sl 

 pair of legs bears 

 the great claws for 

 grasping. 



The life historv of ,, 

 III, 



this crab is I'.'dher com- 



abdomen are very 

 I'udinientary except 

 the sixth jiair. This 

 pail- serves to hold 

 the bod)' firmly in 

 the shell. (.)ne of the 

 pincers is larger than 

 th.e other and both 

 aie used to close the 

 mouth of the shell t(.) 

 keep out intruders. 



Rock crab. — At 



first sight this crab 



resembles a lobster 



cephalothorax, which i.■^ 



iroad in proportion to its 



(.'l-:il», IVctlli t\lv nil 

 the nhdonieu. 



Note 



