522 INFUSORIA. 



ORDER II. 

 HOMOGENEA. 



The body of the Honiogenea presents neither viscera nor other 

 complication, and is frequently destitute of even the appearance of 

 a mouth. 



The first tribe comprises those which, with a gelatinous body 

 more or less contractile in its different parts, still present external 

 organs consisting of cilia more or less strong. 



When they have the form of a horn, (cornet), from which the cilia issue 

 as in the Polypi called Vbrticellse, we have the Ureolaria: when the 

 body is flat, and these cilia are at one extremity, Trickoda: when they 

 surround the whole body, Leucophra: when some of them are stout, 

 and represent species of horns, Kerona: and when these pretended 

 horns are elongated into threads, Himantopes. 



The second tribe consists of those which exhibit no external or- 

 gan whatever, if we except a tail. In 



Cercaria, Mull. 

 The oval body is in fact terminated by a thread. 



Vibrio, Mull. 

 Where the body is round and slender like a bit of thread. 



It is to this genus that belong the 



V. glutlnis et aceii, or the pretended Eels that are seen in vinegar and 

 paste. Those that inhabit the former are frequently perceptible to the naked 

 eye. It is asserted that they change their skin, consist of two sexes, pro- 

 duce living young ones in summer, and eggs in autumn. Freezing will not 

 kill them. The others make their appearance in diluted paste. 



In Enchelis, Mull, the body is softer, oblong, and less determined than that 

 of a Vibrio. In CycUdium it is flat and oval. In Paramecium it is flat and 

 oblong. In Kolpoda it is flat and sinuous. In Gonium it is flat and angular, 

 and in Bursaria hollow like a sac. The most singular genus of the whole 

 is the 



Proteus, Lin. 



No determinate form can be assigned to them; their figure changes every 

 instant, and is sometimes rounded, sometimes divided and subdivided into 

 thongs, in the most odd and singular manner. 



