TUBE-MAKERS. 335 



may be amputated, and it will be restored ultimately 

 to entirety ; and, what is truly wonderful of a crea- 

 ture so complicitly and curiously made, a small 

 portion of the abdominal part has grown to be a 

 perfect individual, having reproduced segments of 

 its own kind, thoracic segments of a different 

 character, and the head and all its garniture and 

 bravery. 



Another tube-worm (Protula protensa) constructs 

 a cylindrical tube from four to five inches long, and 

 as thick as a goosequill, of an opaque chalky white- 

 ness. The head of the animal is furnished with a 

 pair of fan-shaped branchiae, with its yellow fila- 

 ments spotted with scarlet Dr. Johnston kept one 

 of these worms in confinement for several days to 

 watch its movements. "The worm," he says, "would 

 sometimes remain for hours concealed in its shell, 

 and, when it ventured to peep out, the branchial 

 tufts were sometimes slowly and cautiously pro- 

 truded, and sometimes forced out at once, to their 

 full extent. After their extrusion, they were sepa- 

 rated and expanded, and lay at perfect rest on the 

 bottom of the plate, in unrivalled beauty, and an 

 object of never-failing admiration. The worm, how- 

 ever, seemed never either to slumber or sleep ; for, 

 on any slight agitation of the water, occasioned, 

 for example, by walking across the room, or leaning 

 on the table, it would at once take alarm, and 



