HALF AN HOUR WITH CRUSTACEA. 



243 



"Masked-crab " (Corystes Cassivelaunus,~Fig$. 130, 131) 

 may be known from its curious habit of sitting upright, 

 like a dog in the act of " begging." A peculiar crab, 

 much resembling the " Spiny-crab," is a species 



Fte. 131. 



The Female. 



which does not extend further south than the Isle of 

 Man, and accordingly goes by the name of the 

 " Northern Stone-crab " (Lithodes maid). It is covered 



