136 



LIFE, IN ITS INTERMEDIATE FORMS. 



is an annulose one, for its body is composed of an immense 

 number of rings, which, partially slipping one within the 

 other, impart the power of alternate contraction and elon- 

 gation, which is so remarkable in these creatures. 



Scarcely a single oyster can be dredged from deep water 

 — especially if the ground be rocky — which is not more 

 or less covered with shelly tubes, that sprawl and twist 

 over its surface in various contortions, so firmly adhering 

 to it as not to be removed without fracture. Stones, 

 pieces of crockery, broken glass, and all sorts of shells, 

 are liable to be overspread with these white pipes, after 

 they have been immersed a short time in the sea ; and 

 similar structures occur, of a smaller kind, about the 

 pebbles that lie on the shore near low- water mark. These 

 are the dwellings of marine worms called Serpults. 



If we select a shell on which is seated a cluster of 

 these pipes, and put it into a basin of sea-water, we shall 

 soon be delighted with a brilliant spectacle. Let us sup- 

 pose the tubes to be of that kind which is about as thick 

 as a tobacco-pipe, which is adherent for the most part of 

 its length, but rears upwards at its extremity, and displays 

 a smooth circular mouth (Serpula contortuplicata). Down 

 in the depth of the interior we presently discern what 

 resembles a cork of a bottle, gradually pushed up till it 

 reaches the orifice, which it accurately fits. It is a conical 

 stopper, of a brilliant scarlet hue, marked with a number 

 of ridged lines all diverging from the centre. 



The stopper still emerges, and we see that it forms the 

 end of a long slender stem, which is slowly pushed out to 

 make room for other emerging organs in the form of a 

 double fan of scarlet threads radiating from a sort of 



