THEIR SANDY TUBES. 319 



ever seem to be busy in the exercise of their archi- 

 tectural propensities, making alterations, repairing 

 damages, or otherwise ' sorting ' their tubiculous 

 habitations. 



' The tubes of the Sabellae,' says Dr. Williams, 

 ' are soft, flexible, and muddy. Slimy mucus fur- 

 nished by the integumentary glands of the body is 

 the mortar or cement, fine sand molecules are the 

 " stones " or solid material of the architecture. In the 

 Sabellse the lime of which the tubes are built is held 

 in solution in the mucus provided by the cutaneous 

 glands. It is adjusted in the fluid form, and 

 moulded by appropriate tools into the required shape. 

 It then solidifies, too, under water, like the " Aber- 

 thaw lime." The tube of the Sabellae fits closely 

 round the body of the worm ; it is slightly elastic, 

 and the interior is smooth/ 



