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PROTOZOOLOGY 



reproduction. The central capsule becomes very irregular in its out- 

 line and the nucleus breaks up into numerous chromatin globules. 

 Finally the capsule and the intracapsular cytoplasm become trans- 



Fig. 218. Diagram illustrating the probable life-cycle of Actipylea 

 (Kiihn). a, mature individual; b, c, binary fission; d, e, multiplication by 

 budding; f, mature individual similar to a; g, formation of swarmers; h-j, 

 supposed, but not observed, union of two swarmers producing a zygote; 

 k, 1, young individuals. 



formed into numerous small bodies, each containing several nuclei. 

 Further changes are unknown. Swarmer-formation is known in some 

 forms. In Thalassicolla, the central capsule becomes separated from 

 the remaining part of the body and the nuclei divide into a number 

 of small nuclei, around each of which condenses a small ovoidal mass 

 of cytoplasm. They soon develop flagellum. In the meantime the 

 capsule descends to a depth of several hundred meters, where its 



