1 64 



FLORENCE PEEBLES. 



R. 59. The anterior end of a cell was cut off four hours after 

 fission. The nucleated fragment divided irregularly into a small 

 anterior and a large posterior cell. 



R. 30. One monster was obtained from a cell cut five hours 

 after fission. Almost the entire anterior half was removed 

 (Fig. 14, X). The wound closed in very slowly, the fragment 

 increased in size (C), and not until the fourth day after the 

 operation was any sign of division observed ; then a constriction 

 appeared near the anterior end which finally assumed the shape 

 of an individual (Fig. 14, D). On the tenth day the mass 

 divided into two irregular cells (E and F) each containing only 

 one nucleus. It is evident that fission here was not only delayed 

 but the whole mechanism of cell division was thrown out of order. 

 The disturbance here was greater than when the cut was made 

 further forward, and may have been due to injury to the nucleus. 



In these young cells there was no sign of an increased rate of 

 fission after removal of a part of the cytoplasm such as was 

 observed in vegetative cells where three or four divisions followed 

 in quick succession in the first twenty-four hours after the 

 operation. 



G. A Comparison of the Behavior of the Nucleated Fragments from 



Four Different Races. 



In order to compare the power of regeneration in different 

 races four distinct lines were selected and the following table 



compiled. 



TABLE III. 



Such a table as this demonstrates clearly that the power of 

 regeneration varies greatly in different races. It also shows that 

 in all four races there is greater disturbance when the anterior 



