90 DAVENPORT ACADEMY OF SCIENCES. 



BI^EPHARISMA Perty. 



Elongate, flattened, pointed and curved to the left anteriorly, 

 rounded or truncate posteriorly. Oral groove, a deep furrow on 

 the left-hand border usually reaching from the anterior end to the 

 middle of the body where it leads into a short pharynx. A series 

 of large cilia on the left-hand border of the peristome, on the 

 right-hand border, an undulating membrane. Color, some shade 

 of pink or red. 



Blepharisma lateritia Ehr. 



Body somewhat lanceolate, often truncate posteriori)^ Peris- 

 tome reaching to the middle of the body. Undulating membrane, 

 bristle-like in appearance, sometimes not very conspicuous. 

 Nucleus oval, in the anterior half of the body. Contractile vesi- 

 cles posterior. Color, peach-bloom. 



Length, 150 microns. (Fig. 145, Pi. XIX.) 



Found in Eake Okoboji and a few other places of the state. 

 Habitat, fresh water among aquatic plants. Although the organ- 

 ism normally possesses coloring matter, transparent individuals 

 may often be observed. The highly-colored body also immedi- 

 ately becomes transparent on the application of fumes of osmic 

 acid. 



Reproduction is by longitudinal division. 



METOPUS C. & L. 



Usually elongate-oval, but changeable in form, anterior extrem- 

 ity usually twisted obliquely over the ventral surface. Oral 

 groove narrow, furrow-like, extending obliquely from left to right 

 nearly to the middle of the body. Oral aperture at the posterior 

 end of the furrow, opening into a short pharynx. 



Metopus sigmoides Miill. 



Body usually elongate, the anterior extremity twisted over the 

 ventral surface. Cilia covering the entire body but somewhat 

 longer at the posterior extremity. Nucleus oval, situated cen- 

 trally. Contractile vesicle posterior. 



Length, 100-200 microns. (Fig. 146, PI. XIX.) 

 This species is found in pond water at the bottom of old 

 infusions of decaying vegetable matter. A variety of forms may 



