280 MANUAL OF NATURAL HISTORY. 



hands they are enabled to crack the shells of mol- 

 lusks and convey the food to their mouths. In 

 some, as the Mantis-Crabs, these claws are long and 

 prehensile, the moveable thumb being folded in a 

 groove of the tibia. In numerous instances the 

 Crustaceans seem to be the marine representatives 

 of the Insects of the land, the sessile-eyed tribes cor- 

 responding to the Myriapods, and the peduncle-eyed 

 families to the Arachnidans ; the names of others 

 suggest similar analogies, as Spider-Crabs, Scorpion- 

 Crabs, Mantis-Crabs, &c. 



The habits of these animals are extremely va- 

 ried : thus we find some living on the land, as 

 the Gecarcini; others inhabiting sandy places near 

 the sea, as the Horseman-Crabs, which run very 

 fast, and form deep burrows ; others, also living 

 in holes in similar situations, like the Gelasimi, 

 hold up and snap their great disproportioned claw, 

 appearing to beckon with one hand, and hence 

 have been termed Calling-Crabs. The Hermit- 

 Crabs are true pirates, seizing upon the shells of 

 various mollusks, and using them as houses for them- 

 selves, their abdomens being soft and spiral to adapt 

 them to such a mode of life. The Gcenobitce, which 

 live in wide-mouthed shells, have one claw very 

 large to serve as an operculum ; but the Paguri, 

 which inhabit shells with narrow mouths, have both 

 claws equal. Another genus of this family has the 

 abdomen hard, and lives in holes of the mountains; 

 this, which is the Tree-Lobster {Birgus latro), 

 ascends the Palms and devours the fruit, and is in 



