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SIPUNCULACE^E. 



The species bury in sand, or in the crevices of rocks, or, 

 as is the custom of the curious animal before us, adopt the 

 shells of dead univalve testacea for a house and home, after 

 the manner of the Hermit Crab. The Sipunculus would 

 appear, however, to be of a less changeable disposition of 

 mind and body than its crustacean analogue, and when 

 once securely housed in a shell to make that its permanent 

 habitation. Whether the egg is originally deposited in the 

 future habitation of the animal by some wonderful instinct, 

 or is only developed when lodged by the waters in such a 

 locality, or whether the parent Sipunculus bequeaths the 

 chosen lodging of its caudal termination to its eldest born, 

 and so on from generation to generation, a veritable entailed 

 property, we know not at present ; but the inquiry is a 

 most interesting one, and well worth the attention of the 

 experimental zoologist. The Sipunculus is not, however, 

 content with the habitation built for it by its Molluscan 

 predecessor ; it exercises its own architectural ingenuity, 

 and secures the entrance of its shell by a plaster-work of 

 sand, leaving a round hole in the centre sufficiently large 

 to admit of the protrusion of its trunk, which it sends out 

 to a great length, and moves about in all directions with 

 great facility. This trunk is long and cylindrical, and 

 slightly enlarged at its extremity, where it is surrounded 

 by about twenty or more linear-lanceolate tentacula, which 

 are very seldom protruded. Behind these tentacula are 

 four circles of minute bristles. The trunk can be entirely 

 retracted within the bodv. In the lowermost figure I have 

 represented the Sipunculus alive in a Periwinkle shell, of 

 which I have broken away the upper part in order to show 

 the animal's body ; the figure immediately above represents 

 the creature freed from the shell, but with the trunk 

 retracted; and the two uppermost represent the animal 



