smith: infusoria of Kansas. 165 



Onychodromus gra/ndis Stein. 



Body somewhat rectangular, about two and a half times as long as 

 broad. Lateral margins nearly parallel; anterior margin obliquely trun 

 cated on the left side in adult animals. Peristome field broadly triangular, 

 its reflected border with an undulating membrane. Three large anterior 

 styles, followed by three rows of smaller frontal styles; numerous venti-al 

 styles in three or four rows; from four to seven anal styles. Four ovate 

 macronuclei, each with a small micronucleus. 



This species was found several times in pond water. At one time a 

 peculiar modification was present. Each of the marginal setae was fibril- 

 late or branched. This feature occurred in each individual examined from 

 the one culture, but had not been noticed in the earlier cultures. It was 

 probably a local modification. I have noticed that under certain condi- 

 tions the styles of many Hypotricha, normally unbranched, become 

 branched irregularly. 



Lengths range from 104 to 347 microns. Length of type specimen, 255 

 microns. (Fig. 39, plate XLII.) 



Genus Gastrostyla Engelmann. 



Body persistent in form, elongated oval. Peristome triangular, its re- 

 flected border bearing an undulating membrane. Five or six frontal 

 styles; several ventral styles arranged in an oblique row; five or six 

 anal styles; an uninterrupted series of marginal setae, the most posterior 

 usually being the longest. Two or four macronuclei. 



Gastrostyla steinii Engelmann. 



Body elongated oval, narrowest anteriorly, rounded at the extremities. 

 Between two and three times as long as broad. Peristome triangular, 

 about one-third the length of the body. Six long frontal styles; an oblique 

 row and two or three additional ventral styles; four or five anal styles, 

 not projecting beyond the posterior margin of the body. Marginal setae 

 longest at the posterior extremity. Four ovate macronuclei. Contractile 

 vacuole single, located at the left side near the posterior angle of the 

 peristome. 



Length varies from 150 to 330 microns. Length of type specimen, 156 

 microns. (Fig. 41, plate XLII.) 



Genus Oxytricha Ehr. 



Body rather flexible, elongated oval. Three to several frontal styles; 

 a few scattered ventral styles; five anal styles; an uninterrupted series 

 of marginal seta?. Two to four macronuclei. Contractile vacuole single. 



Oxytricha bifaria Stokes. 



Body oval, less than three times as long as broad, narrowest anteriorly. 

 Right border convex, left border concave or flattened. Posterior end 

 bluntly pointed. Seven frontal styles, five scattered ventral styles, and 

 five anal styles. Peristome reaching to the middle of the body, right border 

 ciliated and bearing a narrow membrane. Marginal setae uninterrupted, 

 stronger at the posterior end. Macronucleus usually double. Contractile 

 vacuole anterior to the middle of the body. 



This is described as being a quite variable species. Average length, 

 250 microns. Length of type specimen, 200 microns. (Fig. 45, plate 

 XLIII.) 



