168 TOILERS IN THE SEA. 



strained and forced into its original direction, so 

 that the extremities of the tube, which have re- 

 mained soft and pliant, are pushed onwards, the 

 downward shoot becoming a root-like fibre, and the 

 upper continuing the polypary, and swelling out as 

 before, at stated intervals, into cells for the new 

 development of other polypes." 1 



Undoubtedly the chitinous covering of the polypes., 

 which serves as a protection to their delicate bodies, 

 and a home in which to dwell, is gradually built up, 

 as occasion requires, by absorption and elaboration, 

 from the water of the ocean. These little builders 

 construct their own houses, as the crab and the 

 oyster construct their shells, from material held in 

 solution by the sea-water. These structures may 

 not be so imposing, or so substantial, as those of the 

 architects who construct coral islands, but they are 

 even more beautiful, and equally exhibit a facility 

 for construction 



" Where every one, 



By instinct taught, performed its little task ; 

 To build its dwelling and its sepulchre, 

 From its own essence exquisitely modelled ; 

 There breed, and die, and leave a progeny, 

 Still multiplied beyond the reach of numbers, 

 To frame new cells and tombs ; then breed and die 

 As all their ancestors had done, and -rest, 

 Hermetically sealed, each in its shrine, 

 A statue in this temple of oblivion ! " 



1 Johnston's " British Zoophytes," p. 9. 



