Sketch of the Infusoria of the family Bacillaria. 301 
en 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. 
5th. Action of Todine.—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. 
Iam able by conclusive experiments to confirm Meyen’s state- 
Ments as to the presence of starch in these bodies. In specimens 
gathered in November, many of which I have still by me ina 
living state, I find no difficulty in producing the blue or purple 
color with tincture of iodine. Sometimes, however, the speci- 
men 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 c isti 
color of iodide of starch is then shown most distinctly. I have 
repeatedly treated in this way the large species, C. trabecula (fig. 
32, Pl. 1) as well as others, and have uniformly found that a por- 
tion of the interior takes the blue or purple color. 
I cannot however consider the presence of starch in Rie bod- 
ies as conclusive evidence that they are plants. Is it not possible 
that they are animals which feed, wholly or in part, on amyla- 
ceous matter extracted from the aquatic plants among which 
they live? If so, the detection of starch in their stomachs is 
not surprising. 
6th. Organs of motion and moving papille.—These I have 
hot yet seen, but do not feel authorized to deny their existence, 
as lam 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 suf- 
ficient confidence in its power, or my skill in using it, to contra- 
ct the statements of results obtained by so distinguished an ob- 
Server as Ehrenberg, in using the best instruments of Europe. I 
can vouch very positively for what I have seen, but will not pre- 
tend that ‘end that more may not be seen by others. 
* Made by Charles Chevalier, 130 Palais Royal, Paris. 
