INFUSORIA. 417 



(or seta) affixed to the hinder part of the shell, from which 

 they diverge. In E. truncatiis these are four, but they 

 are wanting in E. charon. The body displays a mass of 

 granules, vacuoles, and vesicles of different sizes. 



These are very beautiful objects ; and their sprightly 

 motions and apparent intelligence give them an additional 

 interest. They crawl more than they swim, running with 

 great swiftness hither and thither, frequently taking short 

 starts, and suddenly stopping. The specimens which we 

 are examining are taken from water which had been kept 

 in a jar for several weeks. The vegetable matters are 

 decaying, and among the stems and filaments this pretty 

 species crawls and dodges about. It seems reluctant to 

 leave the shelter of the decaying solution ; sometimes one 

 will creep out a little way into the open water ; but in an 

 instant it darts back, and settles in among the stems and 

 flocculent matter. Any attempt by turning the glass cover 

 to bring it out into view only makes it dive deeper into the 

 mass, as if seeking concealment. This is about ^r^h of 

 an inch in length of lorica ; and the E. charon is not more 

 than one-fourth of this size. These creatures remind one 

 of an Oniscus, especially when in profile. 



There is an animal very closely allied to these, but much 

 more beautiful, being of a clear greenish translucency, 

 with several vesicles filled with a rose-coloured or purple 

 fluid of much brilliancy. This creature, which bears the 

 name of Chlamidodon, has the peculiarity of a set of wand- 

 like teeth arranged in a hollow cylinder. 



And with these we dismiss the Infusoria, a class of 

 animals which, from their minuteness, the number and 

 variety of their species, their exceeding abundance, the 

 readiness with which they may be procured, and, as it 

 were, made to our hand (by simply steeping vegetable 

 matter in water), and the uncertainty which still prevails 

 as to many parts of their structure and economy ; and 







