132 



PROTOZOOLOGY 



Peranema trichophorum in which the chromosomes were observed 

 to divide transversely (Hartmann and Chagas) as well as longi- 

 tudinally (Hall and Powell; Brown). It is inconceivable that the 

 division of the chromosome in a single species of organism is 

 haphazard. The apparent transverse division might be explained 



SP^ 



1^ 



T2 



Fig. 60. Mitosis of the micronucleus of Concho'phthirus anodontae, 

 X2640 (Kidder), a-c, prophase; d, e, metaphase; f, g, anaphase; h, i, 

 telophase. 



by assuming, as Hail (1937) showed in Euglena gracilis, that the 

 splitting is not completed at once and the pulling force acting 

 upon them soon after division brings forth the long chromosomes 

 still connected at one end. Thus the chromosomes remain to- 

 gether before the anaphase begins. 



In the instances considered on the preceding pages, the so- 

 called chromosomes found in them, appear to be essentially 



