Edwards.] 210 [February 9, 



My notes are of observations made by means of the microscope, 

 and the first is relative to one of those curious atomies of the vegeta- 

 ble kingdom, the Diatomaceae. A few days since (Sept., 18G9) I 

 made a gathering in a ditch communicating with the salt water of the 

 Hudson River, opposite the city of New York, at Weehawken, N. J. 

 Of course the water in the ditch was salt, and, in fact, in it last 

 spring I had caught specimens of Stickleback (G aster osteus) which 

 had come up there from the river to spawn, as is their wont to do. 

 The Ten-spined Stickleback (G. pungitius) I had found very plentiful, 

 and mixed with it a few individuals of the Three-spined (G. aculeatus) ; 

 in fact these fish occurred in such numbers that when the water be- 

 came foul, as it did by evaporation, the bottom of the ditch was lit- 

 erally covered with their dead bodies. The gathering, however, I 

 have to speak of at the present time was made for the purpose of 

 procuring Diatomaceae, and consisted of specimens of an alga be- 

 longing to the genus Enter omorpha, having attached to it more or less 

 firmly numerous Diatomaceae and animals. The commonest form of 

 Diatom was a Cyclolella, and seemingly fixed in some manner to the 

 Enter omorpha, for it was not shaken off by pretty rough usage. How 

 it was fixed I could not detect; most likely by means of a mucous 

 envelope of such tenuity that it is not readily seen. 



The next most common form is the truly wonderful, inexplicable 

 Bacillaria paradoxa, the paradoxical bundle of sticks. Often and 

 often have I spent hours looking at this marvel of nature ; the mo- 

 tion without apparent cause or mode, an invisible joint which, as a 

 friend of mine, an engineer, once remarked, would be a fortune to 

 any one who would discover it, for here we have several sticks forming 

 the bundle, moving over each other without separating, and yet the 

 use of the highest powers of the microscope has failed to detect the 

 means of their union into one mass or composite group of individuals. 

 This grouping of individuals together, which we so commonly find 

 among the. Diatomaceae, as in Schizonema, Achnanthes, Melosira, and 

 a host of other genera, appears to me to have its analogue in the ani- 

 mal kingdom in the Polyzoa; which, although generally fixed, yet at 

 certain periods throw off motile forms by means of which the species 

 is distributed. Do not the Diatomaceae do likewise? I am of opinion 

 that they do, and I shall produce evidence on that point further on. 

 As to the Bacillaria paradoxa, the oftener I watch it the more it puz- 

 zles me. Not long since I saw one specimen (of course I mean one 

 bundle of individuals) slide out to its utmost limit across the field of 



