LIFE AND DEATH. 



123 



imbedded in a jelly. (For figure see below.) This organism 

 cannot however be ' considered as a genuine perfect Polyplastid, 

 for at a certain time the component cells part from one another 

 and then continue to live independently in the condition of Mono- 

 plastides.' These free amoebiform organisms increase considerably 

 in size, encyst, and finally undergo numerous divisions a kind of 

 segmentation within the cyst. The result of the division is a 

 sphere of ciliated cells similar to that with which the cycle began. 

 In fact, Magospkaera is not a perfect Polyplastid, but a transitional 



DEVELOPMENT OF MAGOSPHAEKA PLANULA (after Hackel). 



i. Encysted amoeboid form. 2 and 3. Two stages in the division of the same. 

 4. Free ciliated sphere, the cells of which are connected by a gelatinous mass. 5. 

 One of the ciliated cells which has become free by the breaking up of the sphe're. 

 6. The same in the amoeboid form. 'j. The same grown to a larger size. 



form between Polyplastides and Monoplastides, as the discoverer of 

 the group of animals of which it is the only representative, indi- 

 cated, when he named the group ' Catallacta.' 



According- to Gotte, the natural death of Magosphaera consists, 

 as in the undoubted Protozoa, in a process of rejuvenescence by 

 encystment. The dissolution of the ciliated sphere into single cells 

 ' cannot be identical with natural death. For the regular and 



