THE CELL AND THE TISSUES. 



In recapitulation, the above changes may be tabulated as follows : 

 Resting Mother-Nucleus. 

 Prophases : 



The inauguration of division is marked by migration and 

 division of centrosome, increase of chromatin, resulting 

 in the formation of 

 The Mother- Skein (Spirem) : 

 a. Close skein, 



Disappearance of nucleoli. 

 Disappearance of nuclear membrane. 



FIG. ii. 



R 



Cells from the epidermis of very young larva of newt : A , resting nucleus ; B, close skein ; C, loose 

 skein ; D and E, mother-stars, seen from the polar field and appearing as the wreath stage ; F, mother- 

 star from the side ; G, migration of segments ; //, daughter-stars ; / and J, segments grouped about 

 new polar fields (in J the protoplasm exhibits constriction) ; A", daughter-skeins, division of nucleus 

 complete with slight consiriction of cell-body ; L, completed division of nucleus and protoplasm. 



b. Loose skein, 



Separation of skein into segments or chromosomes. 

 Appearance of polar field around the centrosomes. 

 Rearrangement of chromosomes around polar field. 

 The Mother- Wreath, or Aster: 

 Appearance of nuclear spindle. 

 Metaphase : 



Longitudinal cleavage of chromatin segments. 



