EDMONDSON — PROTOZOA OF IOWA. 59 



Class, INFUSORIA. 

 Sub-class, CILIATA. 

 Order, HOLOTRICHA. 

 Family, ENCHEUNID.^. 



COLEPS Ehrenberg. 



Ovate, persistent in shape. Surface usually deeply furrowed 

 longitudinally and transv^ersely, the furrows bearing cilia. Oral 

 aperture terminal, surrounded by cilia larger than those of the 

 general surface. Posterior border often bearing spines. 



COLEPS HIRTUS Ehr. 



Body barrel-shaped, elongate, cylindrical. Mouth terminal, 

 bordered by tooth-like processes. Posterior border rounded, with 

 three spines. General surface furrowed at right angles giving 

 the appearance of small rectangular, raised areas which are indur- 

 ated. 



Nucleus large, spherical, in the central or posterior region. 

 Contractile vesicle posterior. 



Length, 60 microns. (Fig. 88, PI. XII.) 



Colcps Jiirtus is a very common species in pond water and old 

 infusions. The organism usually appears late in the infusion, 

 after most of the other forms have disappeared, being a scavenger 

 feeding upon decaying matter. Should another infusorian, as 

 ParamcEchan, die, a group of these organisms gather about the 

 dead protoplasm, devouring it rapidly and greedily. The mouth 

 is capable of wide extension during feeding and the body may 

 become nearly spherical, due to ingested material. 



Reproduction takes place by transverse fission, an interesting 

 feature presenting itself in this connection. The constriction of 

 the body commences with the middle transverse furrow, the oppo- 

 site extremities of the dividing cell retaining the reticulate appear- 

 ance, but the newly developed central area bears no furrows. 

 Even after complete .separation one-half of each new individual, 

 bearing the reticular area, is sharply contrasted with the smooth 

 unfurrowed region. After a period of more or less duration the 

 smooth half begins to take on the furrowed appearance and finally 

 reaches the same proportions as the opposite portion. 



