ACTINIA OR SEA-ANEMONE. 485 



1127. These singular organs, which appear to be common to 

 all the animals forming the section called by Leuckart Cizlen- 

 terata (the Polypifera and Hydrozoa), consist of minute capsules 

 or sacs, in the interior of which a slender, wire-like filament may 

 be seen coiled up in a spiral form. On pressure, this delicate 

 thread is suddenly emitted from its containing capsule to a great 

 length, and it is by the agency of a number of these, simultane- 

 ously shot forth from the tentacles, that the latter are enabled to 

 adhere to their prey, whilst from the rapidity with which small 

 animals are destroyed by the grasp of these creatures, and the 

 stinging sensation experienced even by the human skin on com- 

 ing in contact with some of them, it seem probable that some 

 poisonous fluid may accompany the thread. It appears that the 

 thread, or wire, as Mr. Gosse calls it, is not simply protruded 

 from its containing capsule ; in fact, it is attached to the outer 

 extremity of the latter, so that, delicate as it is, it must be 

 thrown out by a process of eversion, exactly as the finger of a 

 glove may be turned inside out. The structure of the threads 

 in the Actinics, as well as in many other forms of the Ccelen- 

 terata, is wonderfully complex ; for their basal part is covered 

 with numerous minute plates, laid over one another like the 

 scales of an artichoke ; and from a portion of this scaly part of 

 the thread, numerous delicate hairs often spring at right angles, 

 so as to give it the appearance of a microscopic bottle-brush. 

 The quantity of these minute capsules is ofiten so enormous that 

 the tentacles would seem to be composed of little else ; and 

 certain species of Sea- Anemones, of which Mr. Gosse has formed 

 his genus Sagartia, have the power of eniitting from pores in the 

 skin long filaments which consist almost entirely of these fili- 

 ferous capsules. 



1128. The digestive powers appear very considerable ; for 

 when Mollusca or Crustacea have been swallowed, the shells are 

 subsequently rejected by the mouth, with not only their soft 

 contents, but even their tendinous and ligamentous portions, dis- 

 solved away. It has been said that the Actinia sometimes 

 swallows a shell, of which it cannot get rid in the usual manner, 

 owing to its broad diameter being turned to the mouth; and 



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