FRESH-WATER RHIZOPODS 



153 



jelly-mass, but on closer examination we find it is 

 attached by an extremely fine stalk, and that it 



Fig. 44. Arcella, Fresh-water Rhizopods (after Leidy). 

 From figth of an inch to 5 ^th of an inch. 



possesses an ornamentally perforated sphere. In 

 one respect it approaches the actinophrys, but be- 

 cause of its beautiful flinty sphere it bears a close 



