210 THE AMERICAN" MONTHLY [Dec 



foot in diameter. Tlie material formed a sediment about 

 one-half inch deep with three inches of water over it, 

 about one quart in all. I placed this in a cool room ex- 

 posed to a strong light. In a few days a curious growth 

 developed at points all over the sediment. This growth 

 resembled a miniature moss, clubshaped, with a dark 

 green top shading from pale green to light brown in the 

 stem. Dozens of these peculiar growths appeared, about 

 one-half inch in height and all very similar in form and 

 coloring. The stem had no elasticity. When pressed 

 carefully down it would remain on the bottom for some 

 time but would finally rise up again upright. I pulled 

 up one of these carefully with tweezers. The part below 

 the mud was dark brown in color and resembled a root. 

 Placing it on a slide under a one-inch coverglass, I found 

 the green top to be composed wholly of desmids, mag- 

 nificent specimens of Microsterias radiosa in all its 

 various types with M. furcata and M. americana and 

 many others, a dozen species of Closterium, as many of 

 Cosmarinm, with Penium, Euastrum, Staurastrura, Doci- 

 dium and many others, some of them unknown to me. All 

 made up a rare collection of varieties which I had never 

 before seen equaled. The stem was made of a tough 

 mucous which contained small varieties of Cosmarium, 

 Penium and Euastrum, but was chiefly filled with minute 

 species of diatoms, Navicula, Amphora, Nitzschia, and a 

 somewhat larger variety which from their darker color 

 and slightly bellows shape I concluded to be developing 

 Surirella. The root was composed chiefly of gelatinous 

 hydrate of iron oxide. By the disturbance caused by 

 the pressure of the cover-glass thousands of the diatoms 

 were liberated and were rapidly traveling to and fro in 

 all directions. These diatoms, were of well-known 

 species, and most of them appeared to be destitute of 

 silex. I considered them immature forms. 



As they were protected to some extent by their gela- 



