34 



MICROSCOPICAL OBSERVATIONS. 

 TABLE C. Continued. 



Descriptions of most of the above species, with figures and copious lists of 

 synonyms, may be found in Ehrenberg's splendid volumes, " Die Infusion- 

 thierchen," and accounts abridged from the same work are given in Pritchard's 

 " Infusoria, Living and Fossil." The latter work was the one I had with me in 

 my Southern tour. 



NOTE. In the preceding tables I have separated the Desmidiefe and Diatomace* from the Infusoria, 

 and I have done so because many distinguished observers now consider these groups as decidedly belong- 

 ing to the vegetable kingdom. While I believe that no accurate line of separation can be drawn between 

 vegetables and animals, I am yet disposed to consider the Desmidieae, from the sum of all their characters, 

 as most nearly allied to admitted vegetables, while the Diatomaceae, notwithstanding Thwaites' interest- 

 ing observations on (heir conjugation, still seem to me, as they have always done, to be true animals. 

 There is such apparent volition in their movements, such an abundance of nitrogen in the composition 

 of their soft parts, and such resemblances between the stipitate Gomphonematse, and some of the Vor- 

 ticellae, that 1 should still be disposed to class them as animals, even if Ehrenberg's observations of the 

 retractile threads and snail-like feet of some of the Naviculse should not be confirmed. 



