150 



SERPULA. 



with here and there a tube, or a portion of a tube, 

 twining itself into the substance. Various algse 

 are often found affixed to the tubes of these 

 creatures. 



Another of these tube-inhabiting worms, or 

 Tubicolous AnneUds, to use the correct term, 

 forms a shelly tube so closely resembling that of 

 the ship-worm, Teredo navalis, that the two are 

 often confounded with each other, especially if a 

 portion only is in question. This is the Serpula, 

 a group of which is given on plate f, fig. 1, the 

 species being Serpula contortuplicata. There are 

 several species of this curious and beautiful worm, 

 one of which, and perhaps the most common, 

 possesses a bayonet-shaped shell, which twists 

 about on the surface of stones or other con- 

 venient substances, and does not erect itself 

 freely. But the species that will be more par- 

 ticularly noticed here, after taking a turn or two 

 upon its support, as if to obtain a firmer basis, 

 and at the same time to determine its direction, 

 shoots boldly upwards. 



Now if a group of these tubes, situated, we 

 will say, on an oyster-shell, be taken into the 

 hand, they will all appear to be empty and 

 useless; but if the tube is not very much con- 

 torted^ a something scarlet may be seen at some 



