OF TEREBELLA FIGULUS. 195 



for building purposes, is, in reality, first eaten by the 

 animal, and, after undergoing a kind of mastica- 

 tion, becomes coated with a salivary secretion, and 

 is then ejected in mouthfuls at the extremity of the 

 tube, which, by such means, becomes gradually elon- 

 gated. The shell work, when deposited as above 

 mentioned, is held in position, and prevented from 

 falling over the outside of the cavity, by the fila- 

 ments which are made to hang down in a most in- 

 genious manner ; the animal, at the same time, putting 

 itself in motion, allows the slimy surface of its body 

 to press and rub against the new addition to the tube, 

 which is thus effectually strengthened and soldered 

 together. 



The animal does not always wait until the open- 

 ing of the tube is reached, but gently disgorging 

 while lying at its ease, it then pushes forward by aid 

 of its head and tentacles the mass of building ma- 

 terial, which soon becomes distributed and moulded 

 to its proper shape. 



If your specimen should happen to build a com- 

 plete tube, its mode of working cannot be well seen ; 

 but should it economize its labours, and run its house 

 up in a semi- circular form against the transparent 

 side of the vessel, as the animal I write of did, you 

 will be enabled to see distinctly every movement 

 that goes on in the interior. 



It seems somewhat singular that the Terebella 

 should possess the power of turning itself within its 



