172 KANSAS UNIVERSITY SCIENCE BULLETIN. 



when contracted. Macronucleus short, oval to bandlike. Contractile 

 vacuole single. Pedicle slender, dichotomously branched; secondary 

 branches long; unbranched portion short. Pedicle longitudinally striated. 



This species was found attached to sticks and weeds in fresh pond 

 water. The suctorian, Podopkrya qitad)ipartita, was often found at- 

 tached to the branches of this species. 



Lengths given for single zooids vary from 75 to 175 microns. Length 

 of type specimen, 85 microns. (Figs. 71 and 72.) 



Epistylis umbilicata C. & L. 



Body elongated oval, anterior end slightly constricted. Peristome 

 not expanded. Ciliary disk has a central projection in the form of an 

 umbilicus. Pedicle dichotomously branched, thick and very short, entire 

 pedicle little longer than a single zooid. Colony composed of but few 

 zooids. 



This colony was found attached to an insect larva which, unfortu- 

 nately, I did not attempt to classify. Epistylis umbilicata is said to 

 occur on the larva of the gnat, Culex pipieus. 



Length of zooids, 50 to 65 microns. (Fig. 75, plate XLVIII.) 



Genus Opercularia Stein. 



Colonial. Stalk branching and rigid. Zooids ovate and ellipsoidal. 

 Ciliary disc attached to one side of the vestibulum, considerably elevated, 

 and closing in a lid-like manner. A hyaline membrane projects from 

 the inner border of the peristome. This genus was first described by 

 Stein as having two sorts of zooids, but this was contradicted later. 



Opercularia Sp. 



Figs. 73 and 74 represent a species which has probably not been de- 

 scribed. It seems undoubtedly to belong to the genus Opercularia. 

 Stalk noncontractile, varying greatly on length and method of branch- 

 ing, which is irregularly dichotomous. The colonies vary greatly, from 

 low, squat colonies of a hundred zooids to very slender zooids, like that 

 represented by Fig. 74, often with not more than twelve zooids, the latter 

 type being the more common. Individual zooids ovate, constricted be- 

 neath the peristome border, widest anterior to the middle of the body. 

 Ciliary wreaths two, a knot-like projection on the center of the disc. 

 Pharynx long and conspicuous, with a prominent pouch anterior to the 

 middle of the body. Macronucleus oval to bandlike. Cuticular surface 

 smooth. Membrane very hyaline and difficult to detect. Transverse 

 folds and a few longitudinal striations usually visible at the posterior 

 end of the zooid. Anterior end generally rounded when contracted, 

 sometimes showing a snout-like projection. 



The queer point about this form is the presence of zooids of two 

 sizes. The small zooids resemble the large ones except for size. There 

 is no regular arrangement of the small zooids, some colonies being en- 

 tirely without them. From their irregular position on the stalk and 

 the fact that they do not occur in groups, it seems clear that they are 

 produced by unequal fission and not by multiple fission. 



This form was found once in great abundance on leaves and sticks 

 in a transient pond. I have not been able, however, to find it again, and 

 for this reason have not described it as a new species. 



