infus6ria. 



163 



but still large cilia extending down the side of the flat 

 surface to the mouth near the center of that part of 

 the body. Four straight, stiff hairs project from the 

 posterior margin, two or them often being divided 

 into fine branches. The back of the Infusorium has 

 no cilia, but is a hard surface^ almost like a shell. The 

 animal is very active. There are several species com- 

 mon among Ceratophyllum and Myriophyllum. 



Fig. i27.-Stylonychia. Fig. i28.-^hilodon. Fig. i29.-I;oxades. 



ig. Stylonychia {Fig. 127). 

 To the beginner the members of this genus will 

 closely resemble Euplotes, as all the cilia are confined 

 to the frontal border, to the part about the mouth, and 

 irregularly distributed over one side of the flat lower 

 surface as walking organs. It can, however, easily be 

 distinguished from Euplotes by its shape, being much 

 more oblong. Sometimes it is long and narrow, while 

 Euplotes is always more or less circular. It has no 

 cilia on the back, which is usually hard and shell-like. 



