﻿1903] BEHAVIOR OF THE CHROMOSOMES 263 



The formation of the granddaughter nuclei presents nothing 

 which demands a special mention. 



Confining himself to the study of the chromosomes In Lilium 

 alone, the investigator would undoubtedly hesitate long before 

 concluding in favor of the double longitudinal splitting of the 

 chromosomes during the first mitosis, because of the variety 

 existing in the form of the chromosomes and their orientation 

 upon the spindle, the difficulty wuth which the double nature of 

 the V-shaped elements which owe their form to a bending is 

 generally' recognized, and because of the extremely complicated 

 character of the chromatin splrem during certain important 

 stages of the second mitosis. The phenomena presented in 

 Podophylhim peltatum and Tradescantia virginica leave no doubt 

 whatever as to the correctness of this view. 



The development of the chromosomes during the prophase of 

 the first division in Podophyllum, as well as other important detail 

 of karyokinesis, have already been fully described in my earlier 

 paper (Mottier, '97), so that only enough of the process w^U be 

 given here to bring out clearly the behaviorof the chromosomes. 



Soon after the segmentation of the spirem into chromosomes 

 the daughter segments tend to become separated except at one 

 or both ends, or they may adhere only near the middle and both 

 ends diverge, as the daughter segments are usually somewhat 

 curved. They may also remain in contact for their entire length, 

 but this is less frequently the case. When the chromosomes are 

 arranged in the nuclear plate they lie, as a rule, tangentially upon 

 the spindle. The daughter segments are more frequently 

 observed adhering at one end only, as \ri fig, 20, but, as in Lil- 

 ium, should the segments adhere at both ends, the ring-shaped 

 chromosome is the result yfig, ig) , It not infrequently happens 

 that both forms of chromosomes are seen in the same nuclear 

 figure. Figs, ig and 20 show the manner in which these chro- 

 mosomes are fastened to the spindle fibers. In those cases in 

 which the daughter segments adhere only at one end, the ends in 

 contact are so closely applied as to give the appearance of a lump 

 or swollen place. This is especially true when the ends of the 

 curved segments are turned directly toward or away from the 



