TUBE-MAKERS. 331 



purpose, is necessarily of small calibre, and is laid 

 horizontally. The inmate protrudes its posterior 

 extremity from beyond the lower end of the tube, 

 and fixes it to any adjacent object, or support, by a 

 glutinous secretion, furnished apparently by the anal 

 segment. When the tube has thus been anchored, 

 the entire attention of the worm is directed to its 

 anterior end, which is raised up, in a more or less 

 erect posture, by continual and incessant additions to 

 the rim of the aperture. To catch and collect the 

 muddy material necessary for the work, the branchial 

 fans are spread out into a semicircle, so that, when 

 the two are brought into contact, a wide funnel is 

 formed. Once in the funnel the muddy water is 

 forced down the rachis of the filaments, by the play 

 of the ciliary fringes, and brought within reach of the 

 singular organ at the base of the funnel, by which 

 the mud is selected and applied, just as a mason 

 would lay lime on with his scoop, and then mould 

 and smoothen it with his trowel. At the base of the 

 funnel, and towards one side, are two external fleshy 

 lobes, or trowels, with an organ like a tongue or 

 scoop between them. Receiving the pellets of mud, 

 the creature mixes it up with an adhesive secretion, 

 furnished probably by the collar of the cephalic 

 segment, and by the organs just mentioned. It is 

 thus rendered consistent and tenacious, and fit to be 

 employed in raising the edge of the tube. To that 



