ON THE MOVEMENTS OE THE DIATOMACE2E. 405 
observations. Tbe rotating movements of some of tbe stalked 
species are thus readily accounted for, while tbe connection of 
the concatenated species wbicb live in chains of several indi- 
viduals, united by their long sides or by their angles, are ren- 
dered intelligible. It is by this hyaline protoplasm that they 
are connected the one with the other. The movements of 
Bacillaria jparadoxa and Bacillaria cur soria, which have so 
much puzzled observers, now receive a ready explanation. 
The Bacillarice are elongated Diatoms attached to one another 
by their broad sides. They are frequently seen to exhibit the 
most strange movements. One frustule slides along its neigh- 
bour until it is only attached to it by its edge ; the next one 
above performs the same movement, and then the whole colony 
follows the example, so that they become spread out like a 
flight of steps ; after a short pause the movement is reversed 
(figs. 7, 8) . This curious phenomenon is easily explained by the 
gliding movement of the hyaline protoplasm of one frustule 
upon that of its neighbour. It may be asked whether Professor 
Schultze's explanation of the movements of Diatomaceas affects 
the question as to their animal or vegetable nature. He him- 
self does not consider that it does, since motile protoplasm is 
as much the property of the vegetable as it is of the animal 
cell. Moreover, it must be remembered that the only satis- 
factory distinction that can be drawn between plants and 
animals is a chemical and functional one. There is nothing 
in Professor Schultze^s observations to lead us to believe that 
the food of Diatoms is organic matter, or that they do not 
build up simple mineral compounds into protein and hydro- 
carbons. 
There is every reason to hope that the observations above 
recorded may serve as the basis for the study of other plant- 
movements, such as those of the Oscillatorise, Desmidiaceas, 
and Alg83-spores. 
BIBLIOGRAPHY. 
Ehrenberg. — 1 . Abhandlungen der Akademie der Wiss. zu Berlin. 1839. 
P. 102 ; 2. Die Infusionsthiercken. 1838. P. 175. 
Focke. — Physiologische Studien. 2 vols. 1854. P. 31. 
Nageli. — Gattungen einzelliger Algen. Zurich, 1849. P. 20. 
Yon Siebold.— Zeitschrift fiir Wiss. Zoologie. Yol. 1. 1849. P. 282. 
Rabenhorst. — Die Susswasser-Diatomeen. Leipzig, 1853. P. 4. 
Smith, W. — A Synopsis of the British Diatomacese. Yol. 1. 1853. 
