EDMOND.SON — PROTOZOA OF IOWA. 65 



This protoplasmic current, illustrated by Figure 98, Plate XIII, 

 no doubt is of assistance in the rapid ingestion of food. 



Didinuun na&utiim has been found in but two, though widely 

 distant, regions of the state. In January, 1904, the species was 

 taken from a small stream near Iowa City in an infusion of sub- 

 merged leaves, and in August, 1905, it was found in Lake Oko- 

 boji among decaying vegetation. 



MESODINIUM Stein. 



Ovate or pyriform, rounded posteriorly, produced into a conical 

 proboscis anteriorly. Oral aperture terminal, puncturing the 

 extremity of the proboscis, at the base of which is a single circle 

 of strong cilia. 



MESODINIUM sp. (?) 



Figure 99, Plate XIII, represents a species not infrequently 

 found in the fresh waters of this state, which is conditionally 

 referred to this genus. 



Body somewhat globose, nearly as broad as long, broadly 

 rounded posteriorly, produced into a snout-like process anteriorly. 

 Oral aperture indistinct but apparently in the distal extremity of 

 the proboscis. Color, green. Nucleus and contractile vesicle 

 concealed. 



Length, 35 microns. 

 . The anterior, snout-like proboscis, which has been observed to 

 be somewhat extensile and contractile and which is apparently 

 punctured at its distal extremity by the oral aperture, has led me 

 to conditionally classify the organism here. Future observations 

 may reveal its true identit}'. So far as I am able to discover, no 

 species of this genus has been reported to be densely green in 

 color, as this organism is. 



LACRYMARIA Ehrenberg. 



Elongate-oval or flask-shaped, nearly cylindrical, somewhat 

 elastic. Anterior extremity usually very narrow, neck-like and 

 sometimes highly extensile and contractile. Oral aperture ter- 

 minal, puncturing a cone-like projection, or an obliquely truncate 

 border. 



LACRYMARIA COHNII (?) S. K. 



Figure 100, Plate XIII, represents a species not infrequently 



JProc. D. a. S., Vol. XI.] 9 [May 25, 1906. 1 



