MARVELS OF THE POND. 131 



We shall first of all see a number of tubes and 

 cells, making together what is called the polypary, 

 or comcecmm, which means a " common house." 

 Then, fixing our attention on one animal, or polypide, 

 as it is termed, we are able to make out oasophagus, 

 stomach, and intestine, the latter bending round and 

 ending in an oval orifice near to the mouth. These 

 are all contained in a bag filled with fluid, and 

 having openings for the mouth and the anus. There 

 is a double system of muscles for the movements of 

 this digestive apparatus. There is a single nervous 

 mass or ganglion on one side of the oesophagus. 

 Around the bag is an investing sheath, from which 

 branch out numerous cells, each occupied by a 

 polypide. 



Out of each bag will be seen slowly rising a 

 number of tentacles, which spread out like the rays 

 of a daisy or the feathers of a pheasant's tail. Over 

 the mouth is a kind of tongue or finger-like process, 

 called the epistome, whose office it seems to be to 

 keep out unsuitable atoms of food which the cilia 

 bring within reach. Just at the point where the 

 stomach ends and the intestinal tube curves round 

 may be seen a long, flexible string, called the 

 funiculus. This goes to the bottom of the cell, and 

 serves to moor the creature in position. Mr. Slack, 

 in his Marvels of Pond Life, to which I am chiefly 

 indebted for the foregoing description, gives us an 

 account of the feeding of Plumatella which he was 

 enabled to observe. He says, " One day a polyzoon 

 caught a large rotifer, which, with several others of 

 its tribe, had been walking over the ccencecium, and 



