ON CRUSTACEA. 307 



of the other cvustacea, is nevertheless capable of a certain 

 degree of resistance, and that a change in its external form 

 would induce others in the principal organs of life. The em- 

 baiTassment of these Crustacea in choosing their retreats would* 

 be still greater, and they would be too much exposed to 

 perish if they were obliged to lodge in shells analogous to 

 those which they had abandoned. All the conditions which 

 nature seems to require are, that the shells shall be univalve, 

 of a capacity proportioned to that of the bulk of the body of 

 the pagurus ; that they should be turbinated at their extre- 

 mity ; and that their mouth or aperture should be accommo- 

 dated to the form, to the thickness, and to the action of the 

 claws, and of the anterior feet of the parasite animal. It 

 moves and walks at the bottom of the sea, or on the shore, by 

 means of its organs of locomotion, and by the pincers of its 

 claws it seizes the little marine animals on which it feeds. 



When menaced with any danger, it retires, as far as is pos- 

 sible, into the interior of its dwelling, and does not show itself 

 until long after the peril has ceased. When seized, it is said 

 to utter a little cry ; but it resists all efforts which can be 

 made to draw it out of its shell, and this cannot be done until 

 after its death. The moments devoted by the paguri to the 

 catching of their prey, those of their amours, and the periods 

 of their change of domicile, are to them times of crisis and 

 danger : they have then to dread a crowd of enemies which 

 devour them, and particularly the fish, which are very eager 

 in their pursuit. These Crustacea, according to the testi- 

 mony of Belon, furnish even an excellent bait to take the 

 fish which frequent the rocks, or which approach the shore. 



But all the paguri do not live in the sea. Le Pere Nichol- 

 son, in his Essay on the Natural History of St. Domingo, 

 describes a species which inhabits the dry places of the sea- 

 shores, and of the hills ; which, when plunged into the water, 

 and even into the fresh water, uses every effort to get out, 



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