INFUSORIA. 



139 



as the Kolpoda, a waving outline. Some, as the Urceolaria 

 present the likeness of a boll or funnel, and appear to be 

 analogous to the Vorticella, in which genus they should pro- 

 bably be included. 



Forms still more irregular are exhibited by other infuso- 

 ria. Of these the most singular is the Proteus (Fig. 78,) 

 which cannot, indeed, be said to have any determinate shape, 



78 



79 



for it seldom remains the same for two minutes together. It 

 looks like a mass of soft jelly, highly irritable and contrac- 

 tile in every part; at one time wholly shrunk into a ball, at 

 another stretched out into a lengthened riband; and again, 

 at another moment, perhaps, we find it doubled upon itself 

 like a leech. If we watch its motions for any time, we see 

 some parts shooting out, as if suddenly inflated, and branch- 

 ing forth into star-like radiations, or assuming various gro- 

 tesque shapes, while other parts will, in like manner, be as 

 quickly contracted. Thus the whole figure may, in an in- 

 stant, be completely changed, by metamorphoses as rapid as 

 they are irregular and capricious. 



The Volvox globator, (Fig. 79) is found in prodigious 

 numbers at the surface of many stagnant pools. Its figure 

 is perfectly spherical ; and its movements consist in a conti- 

 nual and rapid rotation, round its axis, frequently remaining 

 all the while in the same spot. Another species, the Volvox 

 conjlictor, moves by turning alternately to the right and to 

 the left. 



The progressive movements of infusory animalcules are of 

 two kinds, the one consisting in a smooth and equable gliding 



the whole of its alcohol. In this last fluid they sometimes attain so large a 

 size as to be visible to the naked eye. 



