3 12 LESTER W. SHARP 



remembered in interpreting the spirem stages which follow some time 

 later. 



The chromatic material of each chromosome now gradually condenses 

 along a very irregular région around the open spaces and cavities, fig. 2-4. 

 The détails of this process are made ont with no difficulty in fig. 2 and in 

 FIG. 3, which shows a number of détails from différent nuclei. After an 

 inspection of thèse examples it is hardly necessary to say that there is no 

 regularity in the method of condensation. In fig. 3c and f there is a more 

 or less spiral aspect, as is also the case in certain chromosomes of fig. 4, 

 but it is plain from the other examples that no spécial meaning can be at- 

 tributed to the appearance. 



Attention is directed to the great similarity existing between thèse sta- 

 ges and thèse of the telophase, fig. 37, 38. it is obviously necessary to 

 use great care to avoid confusing the two phases. In fig. 4 the whole cell 

 has been represented to aid in making clear this point. Hère the nucleus 

 is large and round and has two large nucleoli. Owing to the thinness of 

 the section and the orientation of the chromosomes the latter are eut into 

 small pièces. The vacuolate cytoplasm is of uniform consistency through- 

 out the cell and contains on ail sides of the nucleus chromatic bodies such 

 as Lundegârdh (io) has described. Moreover ail the walls are of uniform 

 thickness. In contrast to thèse characters are those of the telophase nu- 

 cleus of fig. 37. This nucleus has a shape at once recognized as characte- 

 ristic of the telophase by those familiar with the nuclei of Vicia, is smaller 

 and has a much smaller nucleolus than the prophase nucleus of fig. 4, and 

 is opposed by a sister nucleus of similar constitution in the cell below. 

 From thèse considérations it is clear that the telophase and the prophase 

 hâve not been confused. 



When karyosomes are présent they gradually become indistinguish- 

 able in the condensing bands without lengthening out to double structures 

 such as LundegArdh (io) has described. 



When the thinner portions bounding the open spaces become broken 

 down the condensed chromatic material remains as a very irregular zigzag 

 thread of uneven thickness, which at once begins to straighten out, fig. 5. 

 At the same time the material tends to arrange itself more evenly through- 

 out the length of the thread. AU thèse processes — condensation, leng- 

 thening out, and equalization — go on independently of each other, ail 

 stages being represented in différent chromosomes of the same nucleus or 



