SEEPULiE. 



393 



quite uninterrupted, and no one would imagine that any ex- 

 traneous substance had intruded into the mass. 



The tubes themselves have formed the basis of other sub- 

 marine habitations, for a moderate magnifying-glass shows that 

 sundry molluscs and moUuscoids have settled down upon their 

 exterior, while the white serpentine tubes which creep among 

 the perpendicular pillars, show that the serpulse and other tube- 

 making creatures have taken up their residence in so well pro- 

 tected a spot. 







TEREBELLA CU.XCHILEOA. 



SEKPUIA COXTORTLTLICATA. 



SABEU^ UNISPfRA. 

 8A0ELLA ALVEOL.U{lA. 



At the bottom of the sea there are a vast number of won- 

 derful and interesting animals that are known to naturalists 

 as Tubicolous Annelides, i.e. Tube-inhabiting Wonns. These 

 creatures are true architects, not inhabiting the tubes which 



