160 KANSAS UNIVERSITY SCIENCE BULLETIN. 



This is apparently a somewhat rare species. Found in pond water. 

 Sizes given range from 90 to 122 microns. Length of type specimen, 

 122 microns. (Fig. 28, plate XXXVIII.) 



Family Pleuronemim:. 



Body compressed dorsoventrally or laterally. A long peristome on the 

 ventral side leads to the mouth. Peristomal area provided with one or 

 more undulating membranes. 



Genus Cyclidium Ehr. 



Body persistent in form, oval, compressed dorsoventrally. Oral aper- 

 ture ventral with extensible hood-like membrane. Cuticular surface 

 with fine, long, rigid cilia. One or more long caudal seta? on the posterior 

 border. Contractile vesicle single, posteriorly located. Macronucleus 

 spherical. 



Cyclidium glaucoma Ehr. 



Body ovate, slightly concave ventrally and convex dorsally, about 

 twice as long as broad. Mouth slightly anterior to the middle of the 

 body, supplemented by a hood-like membrane. Cilia very long and 

 slender, arranged in longitudinal rows. Caudal seta? single, twice the 

 length of the other cilia. Macronucleus spherical, nearly central in posi- 

 tion. Contractile vacuole single. 



This is an extremely common form, found both in pond water and in 

 infusions. The fact that the membrane is very difficult to detect makes 

 it liable to be placed in the wrong genus. 



Length, 20 microns. (Fig. 27, plate XXXVIII.) 



Order Heterotricha. 



Ciliata which are entirely ciliated but with an adoral zone of special- 

 ized cilia of great size or fused together into membranelles. These spe- 

 cialized cilia constitute a circular or spiral peristomal series. 



Suborder Polytrichina. 



Heterotricha with a uniform coating of cilia. 



Family Plagiotomid,e. 



Peristomal area a long, narrow furrow, usually extending from the 

 anterior extremity to the mouth. Mouth generally posterior to the middle 

 of the body. Adoral zone extending along the left-hand edge of the 

 peristome. 



Genus Nyctotherus Leidy. 



Body ovate or reniform, somewhat compressed. Peristome cleft-like, 

 extending on the ventral side from near the anterior extremity to the 

 middle of the body, then turning backward and inward to the pharynx. 

 Adoral cilia on the left-hand border of the peristome. Pharynx with long 

 cilia. Anus permanent, connected with a fissure-like rectal passage. Con- 

 tractile vacuole single, subcentral. Macronucleus ovate, anterior to the 

 pharynx. Parasites in amphibians and invertebrates. 



Nyctotherus cordiforviis Stein. 



Body ovate to reniform, compressed, about two-thirds to three-fourths 

 as broad as long. Anterior end slightly pointed. Entrance to pharynx 

 bearing long, stiff setae on its lower edge. Pharynx conspicuous, long and 



