RO'JIKERS. 



225 



mal slipping in between the setae seldom comes out again. 

 The P'loscularia gently contracts the frontal opening 

 and directs the victim towards the preoral aperture 

 where it is gulped down as in Stephanoceros, and the 

 mastax finishes it. Several eggs are often to be seen 

 attached to the foot. 



This splendid Rotifer is common, and where one is 

 found others will usually be near by. 



4. CEciSTES (Fig. 157). 



When a bottle of pond water containing various 

 plants is allowed to stand for a while undisturbed, 

 there will often form on the sides very delicate, thread- 

 like objects, frequently branching 

 and otherwise resembling brownish 

 Algae, waving and trembling as the' 

 bottle is stirred. They are so soft 

 that they can hardly be removed 

 ■with the dipping-tube without break- 

 ing them. They are the sheaths of 

 a Rotifer, which she makes from a 

 sticky secretion exuded by her body, 

 and from small particles of any 

 kinds that may be floating in. the 

 vicinity. The inner surface seems 

 to be smooth, but the outside is 

 rough, irregular, and flocculent. 

 The Rotifer projects from the open 

 end, clinging to the supporting object by means of an 

 expanded, sucker-like foot. As the tube lengthens by 

 the deposit of new material at the summit, she takes a 

 step forward so as to keep her expanded ciliary disk in 

 the open water. If the student will allow a mixture of 



16 



Fig. 157. — GEcistes. 



