264 OCTOBER. 



They hang down in the usual form, to the unassisted 

 eye appearing as excessively slender whitish or flesh- 

 coloured threads, capable of great elongation, or of con- 

 traction into ovate spiral masses, hardly perceptible. 

 But by the aid of the microscope we discern that each 

 tentacle consists of a lengthened fleshy tube, on which 

 are set at pretty regular intervals thickened semi-rings, 

 or knobs, very much like the knobs on the horns of an 

 antelope in appearance. They do not quite encircle 

 the tentacle, and thus one side for the entire length is 

 smooth and straight. These thickened swellings are 

 collections of thread-capsules (cnidce), which are packed 

 as close as they can lie in them, and give to the tentacle 

 that power of adhering by a touch to any animal whose 

 tissues are penetrable, and of benumbing and destroying 

 its vitality, in the manner which I have already, on more 

 than one occasion, alluded to. 



I have not yet described the colours of this jEquorea ; 

 they are, however, exceedingly lovely and beautiful. 

 The crystalline translucency of most of these Medusse, 

 when they are colourless, and of the colourless parts of 

 such as have bright hues, is exquisite in its glass-like 

 purity; in this example the whole of the peripheral 

 portion of the dome is of this hyaline character; but 

 the lower part, which lies just above the flattened roof, 

 is of a lively azure blue, seen to great perfection, when 



