198 THE AMERICAN MONTHLY [July, 



closely resembles that of Rev. Wm. Smith, 1856 ; (see 

 Carpenter) and analagous to the hypothesis enunciated 

 by Prof. H. L. Smith at a Meeting of the American So- 

 ciety of Microscopists, 1887. 



For some reason or other, not fully evident or reasoned 

 out, and as appears in recent works on the Protophytes, 

 Protozoa and Animalcular Infusoria, the motile genera of 

 the Diatomaceae are held to be " simple unicellular 

 plants," or " lowly plant organisms " and are now very 

 generally accepted as belonging to the plant or vegeta- 

 ble kingdom, without any further controverting or chal- 

 lenging as to the grounds or basis of evidence upon which 

 this position is assumed and held. The works of Louis 

 Figuier entitled " The Vegetable World," and "The Ocean 

 World" throw interesting light on the subject of the 

 labors of Dr. Ehrenberg, and other micrographers in 

 connection with the history of the development of the 

 biology of the Infusoria and Diatomacese which apper- 

 tains to the questions previously under discussion, even 

 to the question as to what does or does not constitute a 

 stomach in an Infusorian. 



But without regard to how much or how little Ehren- 

 berg may have done in this special line of investigation, 

 every one interested in the life history of the Diatoma- 

 cese will be permanently indebted to Prof. H. L. Smith 

 for the beautiful colored plates and the descriptive record 

 of his observations, views, etc., thereto made accessible, 

 and within reach of all American students of the Diato- 

 macese. 



Reverting to my observations of living diatoms. I 

 next made a persistent study of several large Navicula 

 nobilis, both in the single and twin or double states and 

 observed very closely the appearances of the endochrome, 

 and other contents, contained within the siliceous frus- 

 tules, when I repeatedly verified in N. nobilis and previ- 

 ously in N. viridis, and divirgens, that the globular bod- 



