CORAL BUILDERS. 



223 



question of digestion, or of circulation and respiration, 

 a few lines must be devoted to the powers, and meanS 

 of attack and defence, possessed by these apparently 

 harmless animals. 



The concealed weapons of the sea-anemones, and 

 their allies, consist in the lasso-cells, stinging-cells, 

 or thread-capsules, as they have 

 been called, which are distributed 

 over the animals in myriads. 

 Gosse has described minutely 

 the different forms, or modifica- 

 tions, of these lasso-cells, but 

 his description is too extended 

 and technical for repetition here 

 (fig. 44). Suffice it to say that, 

 according to Dana, they " are 

 called lasso-cells because the 

 little cell-shaped sheath con- 

 tains a very long slender tubular 

 thread coiled up, which can be 

 darted out instantly when needed. 

 As first observed by Agassiz, the 

 tubular lasso escapes from the 

 cell by turning itself inside out, 

 the extremity showing itself last, and this is usually 

 clone with lightning-like rapidity. Then follows the 

 poison. The lasso-cells are usually less than one 

 two-hundredth of an inch in length, but they are 



FIG. 44. 



LASSO-CELLS OF 

 CORYNACTIS. 



