Courtesy of the American Museum of Natural History 



Fig. 5— A PROTOZOAN COLONY OF BELL-ANIMALCULES 

 (VORTICELLA CAMPANULA) 



Each individual is anchored by a delicate thread of protoplasm which contracts spirally when 



the owner is disturbed. Highly magnified strands of pond scum (Spirogyra) are conspicuous, 



spiral chlorophyll structures showing through the transparent, tubular walls. Two strands are 



forming spores, being connected by ladder-like rungs in the process 



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