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variously coloured vegetable infusions, when on returning them into clear watef, 
he found that the vesicles were filled with the coloured matter. This colour 
disappeared again in a little time, and from this he concluded that the matter 
had acted as the food of the animal, and was digested in the sacs into which it 
had been introduced. These sacs he asserted are connected by little pedicels to 
an internal canal, called by him intestinal, which varies in form, but is so 
constant that Ehrenberg has used it as the basis of his classification of the 
Infusoria. 
At the last meeting of the British'Association Mr. Jones had an opportunity of 
stating personally to Prof. Ehrenberg his objections to some of his conclusions.* 
Prof. Ehrenberg, in a cotemporary Journal, gives an account of this discussion, 
and after stating the views of Mr. Jones, he supplies his own views on the sub¬ 
ject. We cannot pretend to decide which of these anatomists is right; but at the 
same time it must be confessed, that the number of years Prof. Ehrenberg has 
devoted to this subject, his high character for accuracy in other departments of 
science, and his acknowledged skill in the use of the microscope, would lead us at 
present to adopt his views. It is to be hoped, however, that Prof. Jones will 
not rest here, but will prosecute his researches still further in this interesting 
subject. 
Our author also differs from the German professor in another point of the 
economy of these animals. In many of the Infusoria a little red speck has 
been observed similar to the monoculous eyes of many of the entomostracous 
Crustacea , and on this account have been supposed to possess the same function. 
Mr. Jones would appear to infer that these red spots are indications of the 
existence of a nervous system; but is not his reason for objecting to them as 
eyes, as fatal to the supposition that they are a nervous system ? 
The Acalephce (Sea-nettles) form the next class. They are remarkable for 
their gelatinous watery nature; a Medusa weighing five or six pounds if allowed 
to drain away will not leave more than so many grains of dry solid matter. Yet 
their structure and functions are very various. Some are simple plates of 
gelatinous matter, as are the Jelly-fish of our own coasts; others are supplied 
with cilia or tentacula, as in Beroe, and the beautiful Girdle of Venus 
Veneris) ; others possess bladders, capable of being filled with air, by which 
they are floated along; another family has an internal, solid support or skeleton 
in their body, whilst the Diphyda are constructed in such a manner that they 
look like two animals joined together. Weak and helpless as these animals 
appear to be, and little as their system would seem to require nourishment from 
feeding on higher animals, they seize and devour creatures which might seem far 
* See Naturalist , Yol. XY, p. 91. 
