98 DAVENPORT ACADEMY OF SCIENCES. 



UROLEPTUS Ehrenberg. 



Greatly elongated in comparison to the width, and highly flex- 

 ible; rounded anteriorly, posterior extremity extremely narrow, 

 tail-like. Three or four frontal styles, ventral styles in two 

 longitudinal rows; no anal styles. Marginal series of setae set 

 well in on the ventral surface. 



Uroleptus rattulus Stein. 



Body sometimes exceeding in length eight times the width, 

 tapering from near the middle toward the acutely pointed pos- 

 terior extremity, this posterior third of the body being very nar- 

 row, flexible and tail-like. Peristome short, about one-sixth the 

 length of the body. . Nuclei two in number, with the contractile 

 vesicle between them. 



Length, 500 microns. (Fig 164, PI. XXIII.) 



This species has been found in long-standing infusions of 

 decaying vegetation, but is not a common form in this state. 



Movement is by short, interrupted motions, which are character- 

 istic also of other members of this family. 



Reproduction is by transverse division. 



Uroleptus agilis (?) Eng. 



Body four or five times as long as broad, wider centrally, taper- 

 ing posteriorly toward a narrow, bluntly rounded extremity 

 which may be slightly turned to the right. Frontal styles four, 

 several scattered ventral styles sometimes produced in addition to 

 the double row. Marginal setae forming a complete series, pro- 

 jecting beyond tbe border, and somewhat longer in the posterior 

 region. 



Peristome reaching nearly one-fourth the length of the body. 

 Nuclei two in number, in the central region. Contractile vesicle 

 on the left side a little in front of the middle. 



Length, 300 microns. (Fig. 165, PI. XXIII.) 



The plate figure illustrates a form not infrequently found in 

 fresh water in several localities of this state and which, as far as 

 I have been able to determine, corresponds most closely to this 

 species. 



Reproduction and manner of movement as in Urokptus rattulus. 



