ZOOPHYTES 397 



ately long, but diminish regularly as they approach either 

 end. Starting from the side of the tentacle, in the plane 

 of its transverse diameter, these elegant pinnae presently 

 arch downward, but with perfect uniformity and symme- 

 try. By means of the high magnifying power which I 

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

 ened with whorls of knobs, which are accumulations of 

 cnidae, analogous to those which we lately demonstrated 

 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 or- 

 gan 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 downward, for a short distance. These are 

 the reproductive organs, 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 destitute of 

 the fringing convoluted thread. 



The whole surface of the interior the walls, the stom- 

 ach, 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 cil- 

 iary currents hurling along with irregular energy the prod- 

 ucts of digestion, in the form of translucent granules, 

 especially along the edges of the septa. 



