406 EVENINGS AT THE MICROSCOPE. 



circle of these organs is developed around the basal ex- 

 tremity of the vase, and these, every instant becoming 

 more vigorous in their motions, sway the little globe about 

 on its point of attachment. At length the connexion 

 yields, breaks, and the animalcule shoots away, rowed 

 by its hundred oars, to find a new abode, and to found a 

 new colonv. 



Here and there you see shooting through the group, 

 with a rapid gliding movement, an oblong clear body. 

 This is one of the vases, formed by self-division, and 

 exercising its newly-found power of locomotion. It is 

 giddily roving hither and thither, until the instinct of 

 wandering ceases, when it will soberly settle down, affix 

 itself by the point which was formerly its mouth, whence 

 a new stalk will gradually grow, and opening a new 

 mouth in the midst of the new crown of cilia, 



I believe that the division is sometimes transverse in- 

 stead of longitudinal, the cleft occurring by constriction 

 across the middle of the vase; but this I have not seen. 

 In whatever direction it takes place, it is essential that 

 the oblong granular body, called the nucleus, which you 

 see in each vase, be divided, the cleft passing through 

 the middle of this substance, a portion of which is there- 

 fore appropriated to each new-made animal. 



That the essential vitality of the creature resides in 

 this nucleus is shown by another and highly curious 

 mode of increase, namely, that which is effected by 

 encystion. Let us search the live-box carefully ; for, 

 amidst so great a profusion of Vorticellce as we have on 

 this Nitella, it will go hard if we do not find some 

 individuals in the encysted stage. 



Look at this elegant object. It resembles a trumpet 

 of the clearest glass, with a rounded extremity, and with 

 the base affixed to the weed, from which it stands up 

 erect. Within the expanded part of the trumpet there is a 

 turbid mass, with a perfectly defined outline, from several 



