438 



WORMS. 



and open at both ends, but as the animal increases in size it enlarges and extends 

 its tube by adding on layers of calcareous matter to the aperture at the head-end. 



common serpula, Serpula contortuplkata (nat. size). 



The species of the allied genus Sabella exude a gluey substance, and construct a 

 flexible, leathery tube. In some cases these tubes are covered with sand, or 

 pieces of shell, and completely resemble those of the Terebellidce. The species of 

 the genus Amphicora may be found amongst seaweed on the coasts of Europe. 



sabella,. Amphicora sabella (enlarged 30 times). 



The body is short, measuring less than half an inch in length, and composed 

 of a small number of bristle-tufted segments. Unlike the Serpulido}, the animal 

 habitually leaves its membranous tube in search of food, when it appears as 

 a lively little creature, moving with indifference and facility either forwards 

 or backwards. 



