48 DAVENPORT ACADEMY OF SCIENCES. 



The point of insertion of the flagella will aid in the recognition 

 of this minute form. Habitat, fresh water. 



Anisonema trtjncatum Stein. 



Body elongate-ovate, posterior extremity narrowest, anterior 

 border with a shallow concavity at the bottom of which is the oral 

 aperture. Flagella two, the anterior vibratile one about one-half 

 as long as the posterior trailing one. Contractile vesicle anterior. 



lycngth, 30 microns. (Fig. 80, PI. XI.) 



A rare form in this state. Observed only in Johnson county. 

 Habitat, pond water. 



ENTOSIPHON, Stein. 



Oval, somewhat flattened, and of a hardened consistence. Oral 

 aperture in the anterior border, followed by an elongated tube-like 

 pharynx. Flagella two in number, arising on the anterior border. 



Entosiphon sulcatus Duj. 



Body oval, flattened, the anterior border oblique with a deep 

 concavity, at the bottom of which is the oral opening leading into 

 a long tubular pharynx which reaches into the posterior region 

 of the body. Surface of the body grooved longitudinally. Fla- 

 gella two in number, arising from the anterior border near the 

 oral opening, one long, trailing, the other shorter, directed in 

 advance, vibratile. Nucleus spherical, in the posterior region, 

 contractile vesicle anterior. Endoplasm transparent. 



lycngth of body, 22 microns. (Fig. 81, PI. XI.) 



The long cone-shaped pharynx of this species is very conspic- 

 uous. At times it may be partially exserted and owing to its 

 indurated character persists for a long time after the death and 

 decomposition of the organism. 



Frequently found in pond water among aquatic plants. Move- 

 ments oscillating. 



Family, NOTOSOI^ENID^. 



NOTOSOI.ENUS Stokes. 



Somewhat oval and flattened, ventral surface convex, dorsal sur- 

 face concave. Flagella two, the anterior, long one held obliquely, 

 the posterior trailing one ver)^ short. 



