126 ROTIFER A [CH. VII 



Leaving out of sight a few parasitic and aberrant forms, the bulk 

 of the Rotifera are classified as follow : 



Class I RHIZOTA. 



Rotifera in which the foot is not retractile but forms a 

 permanent organ of attachment. The animal lives in a tube. 



Ex. Floscularia. 



Class II. BDELLOIDA. 



Rotifera which creep like a leech, using the foot as a sucker. 

 They are provided with a protrusible adhesive proboscis on the 

 dorsal surface, by which the anterior end of the animal may be 

 made to adhere. 



Ex. Rotifer. 



Class III. PLOIMA. 



Rotifera which swim freely, only occasionally attaching 

 themselves by the forks of the bifurcated foot. 



Ex. Hydatina, Synchaeta, Notommata. 



Class IV. SCIRTOPODA. 



Rotifera provided with hollow movable outgrowths from 

 the body, by means of which they leap, 



Ex. Pedalion. 



