EDMONDSON — PROTOZOA OF IOWA. 93 



represented by the drawing. This species is apparently distinct 

 from Ccvidylostoma patens Miill. in the general contour of the body 

 which, in the forms observed here, has been as described above. 

 In no case was the posterior region the widest of the two extrem- 

 ities and in none of the Iowa forms was a canal-like contractile 

 vesicle present, but usually one prominent vesicle and two or three 

 smaller ones. 



Found in Jefferson county in an infusion of pond water. 



Unidentifikd species. 



Figure 152, Plate XX, represents a species the identity of which 

 is, as yet, undetermined. It has been observed in this state only 

 in Johnson county, in fresh water among algae. 



Body elongate-oval, broadly rounded anteriorly, more acutely 

 rounded posteriorly. Peristome a deep broad depression extend- 

 ing backward nearly to the middle of the body, bearing on the left- 

 hand margin a row of long cilia and on the right-hand a conspic- 

 uous undulating membrane. Pharynx indistinct. Body entirely 

 ciliated. Nucleus large, irregular in shape, central. Contractile 

 vesicle in the posterior region, lateral. 



Length. 250 microns. 



None of the individuals ob.served at any time were brightly col- 

 ored, but very transparent. The character of the oral region and 

 nucleus would ally the form to Blcpharisiua, but the characteristic 

 shape of the body precludes this, nor does it seem to belong to the 

 -genus Condylostoina on account of the nature of the nucleus. 



Family, STENTORID.F:. 



STENTOR Oken. 



Free-swimming or attached. When fully extended, elongate, 

 trumpet-shaped, anterior end truncate, tapering toward a narrow 

 foot which may be attached temporarily to .some support or to the 

 bottom of a soft, mucilaginous lorica. Anterior border bearing a 

 .spiral row of large cilia, the left-hand end of the spiral being the 

 lower, leading into the mouth and s^ort pharynx. Surface striate 

 longitudinally, finely ciliate, sometimes bearing, in addition, long 

 slender setae. Nucleus moniliform, band-like or oval. Con- 

 tractile vesicle in the anterior extremity. 



