TUBES AND HABITS OF SERPUL^E. 273 



careous tubes, which sometimes accumulate in great 

 abundance ; and not unfrequently masses of similar 

 tubes are brought up from considerable depths by the 

 lines of the fisherman. If, while the contained ani- 

 mals are alive, these be placed in a vessel of sea- 

 water, few spectacles can be more pleasing than that 

 which they will speedily exhibit. The mouth of the 

 tube is first seen to open by the raising of an exqui- 

 sitely-constructed door, and then the creature cau- 

 tiously protrudes the upper part of its body, spreading 

 out at the same time two gorgeous fan-like expan- 

 sions, of a rich scarlet or purple colour, which float 

 elegantly in the surrounding water, and serve as 

 branchial or breathing organs (PI. V. fig. 4) . 



The tube wherein the Serpula (such is the name 

 of these beautiful worms) dwells is calcareous, being 

 formed by an exudation from the creature's body, 

 which, even under water, soon hardens into shell in a 

 manner very similar to that whereby other shells are 

 constructed ; and in this tenement the limbless Anne- 

 lide is of course destined to remain during its whole 

 lifetime, fishing for such food as may be obtainable in 

 the immediate vicinity of its residence. 



The habits of these elegant Annelides are neces- 

 sarily extremely simple. Immoveably fixed by means 

 of their tubes to foreign bodies, and frequently at a 

 considerable depth in the sea, all their movements 

 are restricted to the mere act of protruding the ante- 

 rior portion of their bodies to a little distance out of 

 their shelly residence, so as to expose their beautiful 

 branchiae to the influence of the surrounding ele- 

 ment ; these, spread out like fans in the water, are 



N 5 



