INFUSOBIES. 153 



derate length, then almost contracted to nothing ; 

 sometimes they are curved like a leech, or 

 coiled like a snake ; sometimes they are in- 

 flated, at others flaccid ; some are opaque while 

 others are scarcely visible from their extreme 

 transparence. No less singular is the variety of 

 their motions ; several swim with the velocity 

 of an arrow, so that the eye can scarcely follow 

 them ; others appear to drag their body along 

 with difficulty, and move like the leech ; and 

 others seem to exist in perpetual rest ; one will 

 revolve on its centre, or the anterior part of its 

 head ; others move by undulations, leaps, oscil- 

 lations, or successive gyrations ; in short, there 

 is no kind of animal motion, or other mode of 

 progression, that is not practised by animalcules. 

 Their organs are equally various. Some ap- 

 pear to take their food by absorption, having no 

 mouth, to this tribe belong what have been 

 called vinegar eels ; others have a mouth and 

 several stomachs, but no orifice for the trans- 

 mission of their excrements; others, again, 

 have both a mouth and anal passage, and what 

 is wonderful, in such minute creatures, some- 

 times as many as forty or fifty stomachs ; 1 though 

 many are without eyes, others are furnished 

 with these useful organs, some having one, 

 others two, others three, and others four ; some 



1 Leucophrys, Enchelis, &c. 



