120 MICROSCOPY FOR BEGINNERS. 



surface with the adherent spines is lifted up, carrying 

 the spines to one side, and a wave of 

 protoplasm, the body substance, flows 

 out to receive and surround the food 

 brought down by the pseudopodia. It 

 is drawn into the body, the surface 

 closes, and the spines again cover the 



s P ot Tllis ma y happen at an y P art 



of the surface. 

 Acantfwcystis is often found among the leaflets of 

 Myriophyllum, the roots of Lemna, or floating freely in 

 quiet water. It is rarely found in the mud. 



4. ACTINOPHRYS SOL (Fig. 95). 



This is one of the commonest of aquatic microscopic 

 animals. It may be found floating in every quiet pond 

 or pool, or swimming among the leaflets of nearly every 

 gathering of water-weeds. Its body is usually colorless 

 and almost transparent, seeming to be formed of a col- 

 lection of small bubbles, so that it has a foamy appear- 

 ance. It bristles with numerous long, fine rays spring- 

 ing from the whole surface. It moves in a slow, gliding 

 way that has not been satisfactorily explained, but which 

 can hardly be produced by the hair-like rays, for they 

 are motionless, and apparently used only for capturing 

 food. Yet it slowly floats across the field of view, sel- 

 dom changing its shape; or it remains suspended al- 

 most stationary in the water with all its rays extended, 

 and so resembling the pictures of the sun in an almanac 



