SEA-ANEMONES: THEIR WEAPONS 403 



or separate them in various degrees; can perform the one 

 operation in one part, and the other at another, and thus 

 can enlarge or attenuate the general diameter of the cord, 

 apparently at will; and some of these changes can be 

 effected even in the fragment detached from the animal, 

 thus proving that the motile power, whatever it is, is 

 localized in the constituent tissue itself. 



Under pressure the edges of the flattened acontium ap- 

 pear to be thronged with clear viscous globules, overlap- 

 ping one another, and protruding; indicating one or more 

 layers of superficial cells, doubtless forming the epithe- 

 lium. As the pressure is increased, these ooze out as 

 long pear-shaped drops, and immediately assume a per- 

 fectly globular form, with a high refractive power. Below 

 these are packed a dense crowd of cnidce, arranged trans- 

 versely. 



Before we proceed to the examination of these curious 

 organs in detail, it may be well to devote a moment's at- 

 tention to the mechanism by which the acontia themselves 

 are projected from the body. As this was first described 

 (so far as I am aware) by myself, 1 I will take the liberty 

 of citing some of my observations on the matter. 



"The emission of the acontia is provided for by the 

 existence of special orifices, which I term Cinclides. The 

 integument of the body, in the Sagartice, is perforated by 

 minute foramina, having a resemblance in appearance to the 

 spiracula of Insects. They occur in the interseptal spaces; 

 opening a communication between these (and therefore the 

 general visceral cavity) and the external water. It follows 

 that they are placed in perpendicular rows, but I have not 



1 In a memoir entitled "Researches on the Poison Apparatus in the 

 Actiniadse " read before the Royal Society, Feb. 4, 1858. 



