HOMOGENEA. 453 
ORDER II. 
HOMOGENEA. 
The body of the Homogenea 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 Vorticelle, we have the 
Ureovtaria, Lam. 
When the body is flat, and these cilia are at one extremity. 
TRICHODA, 
When they ten £7 the whole body, 
Lrucorura, 
When some of them are stout, and represent species of horns, 
Kerona, 
When these pretended horns are elongated into threads. 
HIMANTOPES. 
The second tribe consists of those which exhibit no external organ 
whatever, if we excepta tail. In 
Cercartia, Mull., 
The oval body is in fact terminated by a thread. To this genus be- 
long (among others) those animalcules which are observed in the 
semen of various animals, and on which so many fantastic theories 
have been founded. 
When this thread is forked, as is sometimes the case, we have the 
Furcocerca of Lamarck. 
Visrio, Mull., 
Where the body is round and slender like a bit of thread. 
It is to this genus that belong the 
V. qlutinis et aceti, or the pretended He/s that are seen in vi- 
negar 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, produce living young ones in 
summer, and eggs in autumn. Freezing will not kill them, 
The others make their appearance in diluted paste. 
