410 EVENINGS AT THE MICROSCOPE. 



protrude beyond its rim. If carmine has been mixed with 

 the water, the atoms are seen in the customary vortex, and 

 some are occasionally drawn into the cell nearly half-way 

 down its cavity, and then swiftly driven out again. On a 

 slight tap upon the table the animal withdraws, and in the 

 same moment the urn bends down upon its leathery 

 pedicle, at a point where there is always an angle, until 

 the rim of the cell is in contact with the plant to which 

 it is attached. This action is instantaneous. Presently, 

 however, it rises, and resumes its former position, and 

 then the mouth of the cell slowly opens, and the animal 

 again protrudes, the cilia appearing first, and finally the 

 head or front part of the animal, which is then opened and 

 begins to rotate. 



Very similar to this are the Vaginicolce, but the cells 

 which they inhabit are not stalked, but are immovably 

 affixed to plants. In F. crystallina, the cell is a tall gob- 



VAOINICOLA. 



let, standing erect, perfectly colourless ; while in F. de- 

 cumbens, it is slipper-shaped, attached along its sides, and 

 of a golden-brown hue, but still quite transparent. Here 

 is, fortunately, a group of the latter species, scattered 

 about the leaves of the Nitella. 



Though, in general, both in form and habits, closely 

 like the Cothurnia, yet the Vayinicola has some peculia- 



