ITS STRUCTURE. 149 



the most hyaline transparency. Such is the polypi- 

 dom, which appears to me to he perfectly homogene- 

 ous, though some ohservers profess to have seen a 

 delicate net-work of vessels ramifying through its 

 walls. This horny tuhe, however, is permeated hy a 

 central core of living flesh, of a thin gelatinous tex- 

 ture, which runs through the whole stalk and through 

 each hranch, without any apparent variation until it 

 reaches the cells. A good microscope shows that the 

 flesh of the polypidom is tubular ; its walls are com- 

 posed of a clear jelly inclosing a loose texture of 

 equally colourless granules. The tubular interior 

 appears to be filled with a subtle fluid, in which mi- 

 nute colourless granules may be seen here and there to 

 move with an irregular quivering dancing motion, to 

 and fro or round and round, but not with any definite 

 order or progression. The motion does not appear 

 to be ciliaiy, but more like that of the granules in 

 the cells of plants, except that it is more minute, 

 and follows no settled order. Intervals occur in 

 which no such motion can be traced ; the dancing 

 globules are very minute and few, but obvious enough, 

 if carefully looked for. 



A little above the bottom of the cell there is a par- 

 tition or false bottom running across, perforated in the 

 centre, because the core of flesh passes through it. 

 From this point may be considered to commence each 

 polype : the body is homogeneous with the fleshy core, 

 which it a little exceeds in thickness, being dilated how- 

 ever into a sort of cushion at the bottom, which rests 

 on the partition. At its upper part it spreads into a 

 star of many rays, very elegantly expanding over and 



