EDMONDSON — PROTOZOA OF IOWA. 89 



linear processes, usually four, radiating from the tip of the tri- 

 chocyst. 



Reproduction takes place by transverse division. 



Family, CYRTOLOPHOSID^. 



CYRTOLOPHOSIS vStokes. 



Ovate, a tuft of hair-like setae, curved distally, extending from 

 the anterior extremity. The organism secreting, when at rest, an 

 enveloping zone of mucilaginous substance. Oral aperture at the 

 posterior end of a short groove on the ventral surface. A series 

 of large cilia on the margin of the oral groove. 



CvRTOLOPHOSiS MUCICOLA Stokes. 



Body elongate-ovate, wider posteriorly, the anterior border 

 obliquely truncate. Cilia of the general surface somewhat rigid, 

 those on the margin of the oral groove longer anteriorly and 

 diminishing in length posteriorly. Nucleus central. Contractile 

 vesicle posterior. Mucilaginous envelope apparent when at rest. 



Length, 25 microns. (Fig. 144, PI. XIX.) 



This strange form has been frequently observed in fresh water 

 infusions among algae and other aquatic plants. As soon as the 

 organism comes to rest a transparent, sticky substance seems to be 

 exuded from the body, its presence and boundaries indicated by 

 granules of various kinds, probably partially excretory, bacteria 

 and foreign particles of diverse nature which adhere to and become 

 imbedded in the .secretion. When' disturbed the organism glides 

 out of this covering and when it becomes quiet again another 

 excreted zone is formed. Stokes, who has created a new family 

 for this species, reports that the "zoocytia" of several individuals 

 may sometimes be united, thereby building up a temporary 

 colony . 



The prominent setae extending from the anterior extremity are 

 very efficient, even when the organism is at rest a powerful cur- 

 rent of water bearing food particles being forced down the oral 

 groove by their vibrations. 



Reproduction is by transverse division. 



Order, HETEROTRICHA. 

 Family, PLAGIOTOMID^. 



[Proc. D. a. S., Vol. ^I.] 12 [June 4, 1906,1 



