INFUSORIA. 
63 
being sometimes globular, then elongating to the left or right, and then becoming globular 
again, in a rapid but very irregular manner. 
4. Presence of distinct circulation. This was noticed many years ago by Gruthuisen. 
The account by Mr. Dalrymple, given in the above extract, agrees exactly with what I have 
seen in several species. The currents are very distinct; so much so, in fact, that they attracted 
my attention before I was aware that they had been noticed by others. 
5. Action of iodine. I cannot otherwise account for Mr. Dalrymple’s statement that iodine 
“ in no instance produced in the Closteria the violet or blue color indicating starch,” than by 
supposing that the specimens he examined were not in the proper state to exhibit it. Meyen 
expressly states, that it is “ at certain times, particularly in spring,” that the starch may be 
detected. 
I am able by conclusive experiments to confirm Meyen’s statements as to the presence of 
starch in these bodies. In specimens gathered in November, many of which I have still by 
me in a living state, I find no difficulty in producing the blue or purple color with tincture of 
iodine. Sometimes, however, the specimen becomes so opaque by the action of this reagent, 
that the purple color of the granules can only be detected after crushing the specimen by 
means of the compressor. The characteristic color of iodide of starch is then shown most 
distinctly. I have repeatedly treated in this way the large species, C. trabecula (Fig. 32, PI. 
21) as well as others, and have uniformly found that a portion of the interior takes the blue 
or purple color. 
I cannot, however, consider the presence of starch in these bodies as conclusive evidence 
that they are plants. Is it not possible that they are animals which feed, wholly or in part, 
on amylaceous matter extracted from the aquatic plants among which they live ? If so, the 
detection of starch in their stomachs is not surprising. 
6. Organs of motion and moving papillce. These I have not yet seen, but do not feel au¬ 
thorized to deny their existence, as I am well aware that my microscope,* although a very 
good one, is probably inferior to the one used by Ehrenberg. It shows the lines on the scales 
of Podura as well as I have been able to see them by any instruments in this country ; yet I 
have not sufficient confidence in its power, or my skill in using it, to contradict the statements 
of results obtained by so distinguished an observer as Ehrenberg, in using the best instru¬ 
ments of Europe. I can vouch very positively for what I have seen, but will not pretend 
that more may not be seen by others. 
I will now proceed to describe briefly some of the most interesting American species of 
Closterium, giving in connection with each the characters of the European species which 
appears to correspond to our own, as far as I can determine by the brief accounts, usually 
unaccompanied by figures, in the works to which I have access. 
Closterium lunula. (Fig. 30, PI. 21.) Semilunar or straight, diminishing gradually towards the rounded 
extremities; internal glands scattered, green granules arranged in several (10) threads, i to yL line; 
* Made by Charles Chevalliee, 130 Palais Royal, Paris. 
