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MICROPHYTES. dat 
often the only reward of a day’s labour, here, in the quiet of 
my study, I may discover in a few atoms of flint, or grains 
of chalk, picked up by the road-side, the fossil remains of 
beings as interesting and extraordinary as the extinct colossal 
reptiles of Tilgate Forest. 
The microphytes, or fossil Diatomacez, described in a 
previous chapter, (ante, p. 93,) were formerly classed with 
_ the organisms that now claim our attention, under the name 
_Infusoria ; from the belief that generally prevailed among 
naturalists, of their animal origin. In fact, some eminent 
microscopic observers, while admitting the vegetable character 
of Xanthidium, Micrasterias, &c. consider the Navicule, , 
- Ennotie, é&c. as belonging to the animal kingdom. 
Thus Dr. J. WW. Balog in a late “ Memoir on the Micro- 
scopic Organisms i in Various Localities of the United States,” 
divides these bodies into three groups; viz. Infusoria, Desmi- 
diew, and Diatomacece ; with the remark, that he has sepa- 
rated the two latter tribes from the Infusoria, because so 
many distinguished naturalists consider them decidedly to 
belong to the vegetable kingdom: “but,” he adds, “ while 
I believe that no positive line of separation can be drawn 
_ between certain animals and vegetables, I am yet disposed 
to regard the Desmidiec, from the sum of all their characters, 
as most nearly allied to admitted vegetables; while the 
_ Diatomacee, notwithstanding Mr. Thwaites’s interesting ob- 
_ Servations on their conjunction,* still seem to me, as they 
have always done, to be true animals. There is such appa- 
rent volition in their movements, such an abundance of 
nitrogen in the composition of their soft parts, and such 
* The mode of fructification, or conjunction, as it is termed, in the 
_ Algze, consists in the adhesion of two cells or frustules together, and 
their fusion into one; from their united contents a mass of granular 
substance is produced, that becomes consolidated and forms the 
Spore or fruit, which, when arrived at maturity, is set free by the 
bursting of the cell. Mr. Thwaites has ascertained that the fructifi- 
cation is similar in the Diatomacez. 
VOL. I. Z 
