460 EVENINGS AT THE MICROSCOPE 



cella, forming, when in swift action, a filmy ring above the 

 margin, along which, as if upon a wheel, one or more 

 dark points are frequently seen to run swiftly round; the 

 optical expression, as I presume, of a momentary slacken- 

 ing in the speed of the wave. The act of self -division 

 takes place in this animal, as in the Vorticellce; and it is 

 curious to see two Vaginicolce, exactly alike, lovingly in- 

 habiting the same cell. One of the cells which we are 

 now examining is in this doubly tenanted condition. 



I will now exhibit to you some examples of the most 

 highly organized forms of this class of animals, in which 



VAGINICOLA. 



we discern a marked superiority over any that we have 

 yet looked at, and a distinct approach to those animals 

 whose more precise movements are performed by means 

 of special limbs. These creatures are excessively com- 

 mon, both in fresh and sea water, wherever vegetable mat- 

 ter is in process of ^decomposition; and hence their pres- 

 ence can at all times be commanded by keeping infusions. 

 In this old infusion of sage leaves, for instance, they occur 

 in vast multitudes, past all imagination; as you may see 

 with a lens in this drop. 



This group belongs to the genus Stylonychia, and I 

 believe to the species S. pustulata. It presents the form 



