290 



EVENINGS AT THE MICROSCOPE. 



we will look at one at a time. A long narrow tube, 

 slightly widening at the mouth, is affixed by the lower 

 extremity to the slender filaments of 

 water-grass, crowfoot, &c. It is about 

 one-fifty-fifth of an inch in length, pellu- 

 cid but tinged with brownish yellow. It 

 appears to be of a gelatinous texture, and 

 is covered with extraneous substances, 

 such as decaying animal or vegetable 

 matters, which adhere to its surface. 

 From the mouth of the tube protrudes a 

 transparent colourless animal, the head 

 of which is rounded, with the extremity 

 pursed up. Suddenly it unfolds its 

 flower-like wheel, which consists of two 

 broad nearly circular lobes united, the 

 margin of which is set with strong cilia, 

 much resembling those of the last species. 

 Each cilium appears to be curved, and 

 to be thickened at the middle — the op- 

 tical expression of the ciliary wave ; 

 and the efiFect of the rotation, as each seems to pursue 

 its fellows around the circular course down the divid- 

 ing sinuosity, on the opposite sides, and around the 

 margin again, is very striking. The cilia at the front 

 are interrupted between the lobes. In the centre of 

 each lobe is a broad plate, surrounded by a bright 

 ring, and crossed by radiating lines which also extend 

 towards the ciliated margin ; probably these are mus- 

 cular filaments. The funnel is between the lobes, and 

 leads by a short oesophagus to a bulbous transparent 

 mastax, in which are seen jaws that work on each 

 other. Below this is a long capacious sac, without con- 



TWO-LIPPEP 

 TUBE-WHEEL. 



