410 



EVENINGS AT THE MICROSCOPE. 



round with cilia. Often the animal performs its ciliary 

 vibrations within the shelter of its house, not venturing 

 to 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 clown 

 upon its leathery pedicle, at a point w^here 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 instan- 

 taneous. 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 appear- 

 ing 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 V. crystalline^ the cell is a tall 



VAGI-MCOLA. 



goblet, standing erect, perfectly colourless ; while in 

 V. decumbens, it is slipper-shaped, attached along its 

 sides, and of a golden-brown hue, but still quite trans- 

 parent. Here is, fortunately, a group of the latter 

 species, scattered about the leaves of the Xitella. 



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



