60 ANTHOZOA. 



magazines of these weapons. Certain species of 

 Actinia have the faculty of shooting forth from 

 orifices scattered over the surface of the body, slender 

 white filaments in great profusion, coiled up so as to 

 resemble tangles of sewing cotton. The slightest 

 touch is sometimes sufficient to make these filaments 

 shoot forth from various points with great force and 

 rapidity. They have a strongly-adhesive power, 

 which is dependent upon a very wonderful me- 

 chanism. On being examined with a microscope, 



FIG. 41. AKIUAL FLOWERS j l. Actinia Alcyoncides; 2, A. Gemmacea. 



the entire surface of the tentacula and the cotton- 

 like threads are seen to be densely crowded with 

 transparent oval vesicles, in each of which is coiled 

 up a delicate filament, often thirty or forty times 

 longer than the capsule which contains it, and more- 

 over this lasso-thread is variously armed with sharp 

 barbed spines of inconceivable minuteness, but formid- 

 ably effective for their purpose. On the slightest irri- 

 tation, the spiral-thread bursts forth and entwines the 

 victim in its spiny folds, which seem to be armed 



