300 MEDUSOID or CAMPANULARIA. 



contraction or expansion. No thickened edge marks 

 the orifice, which can he discerned only hy delicate 

 manipulation. The whole of this truncate surface is 

 marked with the most evanescent concentric corru- 

 gations. 



We return now to the marginal canal. At each of 

 four equidistant points, quadrating the circle, there 

 springs from the canal a filamentous tentacle of great 

 length, with a hulhous root. When extended it may 

 he ahout twice as long as the diameter of the whole 

 glohe, hut it is usually much contorted ; and especial- 

 ly when swimming, the whole filament being then so 

 contracted and twisted together, as to appear only an 

 oblong knob, very little larger than the bulb alone in 

 its ordinary state. The filament is distinctly tubular 

 throughout; and the bulb has an enlarged cavity pro- 

 portioned to its size, which evidently communicates 

 with the marginal canal (Fig. 6j. The bulb is filled 

 with a yellowish granular matter, which does not extend 

 into the tube of the filament. The walls of the filament 

 are composed of oval grains (filiferous capsules, no 

 doubt) set in a clear glairy matter, transversely to 

 the length, and radiating from the centre, their tips 

 projecting on all sides. Towards the extremity, the 

 surface becomes more and more tubercled and rugged, 

 and at length is studded with sharp conical points 

 irregularly set: the very tip being slightly dilated 

 into a rounded bulb (Fig. 7). 



I observe that the globe no sooner is at rest by 

 touching the bottom of the vessel, that it unfolds and 

 extends the four filaments, still however corrugated 

 and contorted : probably for the purpose of entwining 



