132 SKETCH OF THE INFUSORIA 



see them by any instruments in this country, yet I have not 

 sufficient confidence in its power, or my slviii in using it, to con- 

 ti'adict the statements of results obtained by so distinguislied an 

 observer as Ehrenberg, in using the best instruments of Europe. 

 I can vouch very positively for v^hat 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 inter- 

 esting American species of Closterium, giving in connection with 

 each the characters of the Eviropean species which appears to 

 correspond to om- own, as far as I can determine by the brief 

 accounts, usually unaccompanied by figures, in the works to 

 which I have access. 



1. Closterium lunula. (Fig. 30, PL I.) Semilunar or straight, di- 

 minishing gradually towards the rounded extremities, internal glands 

 scattered, green granules arranged in several ( 10) threads, one quarter 

 to one twelfih of a line. 



2. Closterium monilif cram. (Fig. 31, PL I.) Semilunar, never 

 straight, smooth, acute, and rounded at the ends, internal glands in 

 the middle of the body arranged in a moniliform manner, green 

 granules in several rows, of which the three middle ones are most 

 distinct. 



Specimens agi'ceing with the characters of each of the above 

 species are common in this country. They do not however ap- 

 pear to be specifically distinct. They may be easily recognized 

 by their smooth, green, crescent-lilvc forms. 



3. Closterium trahecvla. (Fig. 32? PL I.) Straight, cylindrical, 

 contracted in the middle, smooth, the ends truncate, glands scattered 

 or in several series, numerous obscure bands, one twelfth to one fifth 

 of a line. 



I have seen no figure of this European species, but I never- 

 theless venture to refer to it, the fine species represented in figure 

 32. This is the largest Closterium which I have seen in the 

 United States. It occm's at West Point, at Staten Island, and 

 in Virginia. 



Its motions are quite distinct, the cavities containhig moving 

 particles very apparent, and what aj^pear to be terminal openings 

 may be easily seen. By application of tincture of iodine, and 



