SEA-ANEM02yES I THEIR WEAPONS. 425 



treniity runs off to a finely attemiatcd point, tlie whole 

 of the spire visible even to the last, tlio whole bearing 

 no small resemblance to a multispiral sliell ; as one of 

 the CerUhiadcB or Tiirritelladoi. The edhorceum, is dis- 

 charged reluctantly from this form, and I have never 

 seen an example in wliich the wliole had been run off. 

 So excessively subtile are the walls of the C7iidce, that 

 it was not until after many observations that I detected 

 them : in an example from T. crassieornis, which had 

 discharged about half of the wire, I have not seen the 

 slightest sign of armature on the cctJiorceuin. So far as 

 my investigations go, these Sjnral Cnidce are confined 

 to the Avails of the tentacles, in which, however, thcj 

 are the dominant form." 



Such, then, is the form and armature of these 

 organs. But I have not yet done Avith them. The 

 emission of the wire, strange to sa}^, is a process of 

 distinct eversion from beginning to end. The ecthorcBum 

 is not a solid, but a tubular, prolongation of the walls 

 of the cnida, turned-in, during its primal condition, like 

 the finger of a glove drawn into the cavity. Of this 

 fact you may convince yourself by a careful watching 

 of the phenomena before you. Many of the ecthorcea 

 from the tangled cnidce now under your eye run out, 

 not in a direct line, but in a spiral direction. Select 

 one of these, and you will perceive that each bend of 

 the spire is made, and stereotj-ped, so to speak, in suc- 

 cession, while the tips go on lengthening ; the tip only- 

 progresses, the whole of the portion actually discharged 

 remaining perfectly fixed ; which could not be on any 

 Dther supposition than that of evolution. 



In the discharge of the cJianibered kind — to revert 

 to those which we were just now examining — we saw 



