404 EVENINGS AT THE MIOEOSCOPE. 



transverse diameter, these elegant pinnae presently arch 

 downwards, but with perfect uniformity and symmetry. 

 By means of the high magnifying power which I have 

 now applied, each of these pinnas is seen to be rough- 

 ened with whorls of knobs, which are accum.ulations 

 of cnidse, analogous to those which we lately demon- 

 strated in the tentacle of Laomedea. 



In the midst of the area surrounded by the petal- 

 like tentacles, a narrow slit opens into the stomach. 

 This organ is a flat sac, resembling an empty pillow- 

 case hanging down in the centre of the column, and 

 open at the lower end. From this end, which does 

 not extend to more than one-sixth of the depth of the 

 cavity, three threads, much convoluted and irregularly 

 thickened, spring off at each side and arch downwards, 

 for a short distance. These are the reproductive or- 

 gans, which fringe the free edges of as many delicate 

 membranes which run up as perpendicular partitions 

 between the stomach and outer wall, uniting with 

 both, and thus dividing the space surrounding the 

 stomach into chambers open at the bottom. There 

 are eight of these septa, but one on each side is desti- 

 tute of the fringing convoluted thread. 



The whole surface of the interior^ — ^the walls, the 

 stomach, and the septa — is clothed with fine vibratile 

 cilia, by the action of which constant currents are 

 maintained in the water, which bathes every part of 

 the cavity, freely entering at the mouth. "We can 

 distinctly trace these ciliary currents hurling along 

 with irregular energy the products of digestion, in the 

 form of translucent granules, especially along the 

 edges of the septa. 



Though the substance of the polype be soft and 



