303 Sketch of the Infusoria of the family Badllaria. 



I will now proceed to describe briefly some of the mos); inter- 

 esting 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 ac- 

 counts, usually imaccompanied by figures, in the works to which 

 I have access. 



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

 minishing gradually towards the rounded extremities, internal glands 

 scattered, green granules arranged in several (10) threads, ^ to y^ line. 



2. Closterium moniliferum. (Fig. 31, PI. 1.) 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 agreeing 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-like forms. 



3. Closterium trahecula. (Fig. 32? PL 1.) Straight, cylindrical, 

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

 or in several series, numerous obscure bands, ^V to ^ 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 occurs at West Point, at State n Island, and in 

 Virginia. 



Its motions are quite distinct, the cavities containing moving 

 particles very apparent, and what appear to be terminal openings 

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

 then crushing the specimen under the compressor, starch glo- 

 bules may easily be detected. In crushing, the globules are of- 

 ten forced out at the terminal openings, and on relieving the pres- 

 sure are drawn back again. No rupture of a membrane at these 

 points was perceived. 



4. Closterium digitus. (Fig. 33 ? PL 1.) Straight, oval, cylindri- 

 cal, four or five times longer than broad, smooth, the ends very much 

 rounded, sometimes showmg traces of a spontaneous triple division, 

 longitudinal bands often denticulate, ^-V to yV li'^s. 



With this account may be compared fig. 33, PI. 1, which rep- 

 resents a species not uncommon at West Point, and which I have 

 also seen in Rhode Island, Virginia, and Ouisconsin. 



