"run!L"lay rC'] Notes OH Dtafomoceie. 249 



these relations are thus closely established, we cannot but feel, not- 

 withstanding the disadvantage he laboured under in the possession 

 of an inferior instrument, that Ehrenberg manifested more scien- 

 tific and practical acumen in his arrangement of this Family than 

 subsequent writers, who, fortified both with superior appliances and 

 with the ground to work upon that he had previously cleared, have 

 sought to upset this for modifications of their own, and that under 

 less excusable conditions they are equally at fault with the great 

 Professor whom they have twitted with the frequency of his mis- 

 takes in insisting on unimportant and inconstant particulai's as 

 generic and specific characteristics. 



VI. — Notes on Diatomacese. 



By Professor Arthur Mead Edwards. 



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

 the first is relative to one of those curious atomies of the vegetable 

 kingdom, the Diatomace^. Some time since I made a gathering 

 in a ditch communicating with the salt water of the Hudson Kiver, 

 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 {Gastei'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 plentil'ul, and 

 mixed with it a few individuals of the Three-sjsined {G. aculeatus) ; 

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

 became foul, as it did by evaporation, the bottom of the ditch was 

 literally 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 Enteromorpha, having attached to it more or 

 less fii'mly numerous Diatomacese and animals. The commonest 

 form of diatom was a Cyclotella, and seemingly fixed in some 

 manner to the EfiteromorjjJia, for it was not shaken off by pretty 

 rough usage. How it was fixed I could not detect ; most hkely 

 by means of a mucous envelope of such tenuity that it ia not readily 

 seen. 



The next most common form is the truly wonderful, inexplic- 

 able Bacillaria imradoxa, the paradoxical bundle of sticks. Often 

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

 motion 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, 



