168 KANSAS UNIVERSITY SCIENCE BULLETIN. 



This small species is very common in pond water. An accurate draw- 

 ing is difficult to get because of its small size and the fact that it per- 

 sistently climbs around and around some small particle of debris. When 

 not thus supported, as Dr. Edmondson points out, it tumbles about in a 

 very clumsy fashion. 



Average length, 35 microns. (Fig. 50, plate XLIV.) 



Order Peritricha. 



Ciliata in which the cilia have been greatly reduced. Cilia usually 

 restricted to the adoral zone but occasionally being present in the form 

 of secondary wreaths. 



Family Vorticellid^e. 



Body often cup- or bell-shaped. Celia reduced to a dexiotropic, spiral 

 adoral zone, and a secondary posterior wreath which may be present or 

 wanting, permanent or temporary. Forms attached or unattached. 



Subfamily Urceolarin^e. 



Forms having a permanent secondary wreath of the cilia and an in- 

 closed adhesive disc, but no contractile peristomal fold. 



Genus Trichodina Ehr. 



Forms parasitic, usually solitary and unattached. Body discoidal, 

 conical, or cylinderical. Mouth eccentric. Adoral wreath spiral, lead- 

 ing into a short pharynx. Posterior extremity with a fringe of long 

 cilia, and reinforced by a horny ring and denticles. Macronucleus 

 moniliform or band-like. Contractile vacuole single, near the inner end 

 of the pharynx. 



Trichodina sp. 



This animal was found within the shell of a small living snail (Physa 

 — ) . I have been unable to classify it as to species, though it agrees 

 in many respects with Trichodina pedicidus Ehr. Body discoidal, never 

 hourglass shape, equal in length to about two-thirds diameter. Cilia 

 of the posterior end longer than those of the adoral wreath. Horny ring 

 of the posterior region supplemented by an outer and an inner series 

 of denticles. Macronucleus moniliform. 



Width of type specimen, 80 microns; length, 50 microns. (Figs. 66 

 and 67, plate XLVI.) 



Family Gyrocorid^e Stein. 



Free-swimming Peritricha, persistent in form. Body ovate or pyri- 

 form, with one or more ciliary wreaths. Oral aperture lateral or ventral. 

 Anal aperture postero-terminal. 



Genus Telotrochidium S. K. 



Body oval or campanulate. Ciliary circles two. No caudal appen- 

 dages. Mouth ventral, behind the anterior wreath of cilia. Anal aper- 

 ture postero-terminal. 



Telotrochidium sp. 



Fig. 64 represents a species which undoubtedly belongs to this genus, 

 though no postero-terminal anal aperture was observed. Body oval, 

 narrowest at the anterior end. Anterior border thickened. Pharynx 



