34 Anatomy of Sagartia Schilleriana [No. 1, 



an open flower of one of the Composites. The tentacles reach far 

 beyond the diameter of the column, of which only the lower portion 

 is visible ; the body is perfectly transparent, allowing all the internal 

 organs to be traced without difficulty, the lips of the mouth are 

 slightly prominent ; the water is seen moving up and down in the 

 hollow tentacles, which play about actively in all directions, being 

 strongly inflated at their roots, and gradually becoming thinner to- 

 wards their tips. 



None of the Actinozoa possess special organs of sensation, though 

 they are highly sensitive to the touch of any solid body, and even to the 

 influence of radiating heat, or to the light. The fact is that their entire 

 body, when soft, and not covered by a thickened epidermis, is almost 

 throughout equally sensitive and, therefore, makes special organs of 

 sensation superfluous. Still, I should think, there must be an in- 

 timate connection of some kind of nervous system through the entire 

 organism, inasmuch as the slightest touch of the tip of a tentacle is 

 sometimes momentarily communicated to the whole body, its effect being 

 exhibited by a change of the whole form of the body. 



Thus a slight unusual movement of the surrounding water, or the 

 coming into contact with a solid object, causes the Sagartia, when 

 expanded partially, to contract, by which a quantity of the water con- 

 tained, is always ejected through the existing openings, (einclides). In 

 this position, (pi. X. fig. 3) the animal forms a short column, with the 

 upper margin [of which I shall speak as the collar'] somewhat thick- 

 ened, the aperture hidden, and the tentacles protruding about one- 

 forth of their length ; the transparency of the body slightly dimin- 

 ishes ; a few acontia are usually seen to rise from the central portion 

 of the base, being then forcibly ejected through the einclides, at or near 

 the collar. Sometimes the tentacles are laid down, very slightly protrud- 

 ing, forming a sort of a broad cone ; and then viewed from above, they are 

 seen arranged most regularly : those, belonging to the different circles, 

 being easily traceable from their thickness, (see pi. X. fig. 2). Any fur- 

 ther disturbance generally induces the Sagartia entirely to contract, its 

 form resembling in this position a short, depressed conical heap, (see pi. 

 X. fig 4), leaving only a small opening in the upper centre, from which 

 usually the white tips of the primary tentacles slightly project. In con- 

 sequence of the contraction of the outer muscular layer,- chiefly consisting 



