XXII. 



WITH the exception of the Balani (Acorn-Barnacles), 

 perhaps the most common objects to be met with at 

 the sea-shore are the Serpulse. Scarcely a rock, or 

 shell, or bit of old china, or piece of wood, or rusty 

 nail, lying near low- water mark, but is encrusted 

 with colonies of these animals. I have a small twig 

 of a tree by me, so thickly coated with Serpulse as 

 to obscure all signs of its ligneous character, except 

 at each end. A shell also exhibits the same pheno- 

 menon, and well-nigh defies the most skilful observer 

 to define its original form with any degree of cer- 

 tainty. 



The shelly tubes of these animals are built in the 

 form of serpents, or twisted funnels, of a milk-white 

 colour. Although so extremely hard, these tubes 

 are formed solely by an exudation from the body of 

 the animal a simple marine worm. Unlike its 

 erratic friend, the earth-worm, the Serpula is seden- 

 tary in its habits, and at no time does it ever leave 

 its dwelling. 



