CHROMOSOMAL VESICLES IN PHASEOLUS. 213 



found with only four, three or two masses of chromatin within 

 them (Figs. 5 and 6). Fig. 6 illustrates two of these bodies in 

 the act of joining. 



As pointed out above the vacuolization of the proximal portion 

 of the chromatin mass tends to turn the outer ends of the linin 

 strands outward from the long axis of the cell, while the clumping 

 of the solid ends of the chromosomes drags their other end towards 

 a somewhat central point in the nucleus, resulting in the strands 

 radiating from the chromatin mass, which might now be termed 

 the nucleolus or karyosome, like the spokes of a wheel from the 

 hub. The above gives only a two dimensional view of the process 

 which, naturally, is not complete. The chromosomes migrate to 

 the poles of the spindle covering it all the way around, conse- 

 quently, when the proximal ends of the chromosomes swell and 

 the distal ends join to form the nucleolus the linin strands 

 radiate from the nucleolus, not like spokes from a hub, but like 

 spines from the body of a bur. 



When all of the small masses of chromatin first join to form the 

 nucleolus the latter body is irregularly shaped, but it rapidly 

 assumes the spherical form typical of nucleoli of resting nuclei. 

 Fig. 8 represents a dividing cell in which the nucleolus in one of 

 the daughter nuclei is almost spherical while that in the other 

 daughter nucleus is irregular. 



Inter phase and Resting Nucleus. The term "interphase" is 

 used to signify the interkinetic period in the rapidly dividing cells 

 of the root tip while the nuclei farther up the root that are divid- 

 ing slowly or not at all will be called "resting" nuclei. The 

 interphase nucleus exhibits a relatively large nucleolus which 

 may contain one or more achromatic globules, and relatively 

 little scattered chromatin. The linin strands which, as shown 

 above, represent the line of contiguity of adjacent chromosomes, 

 are quite evident in such nuclei. The few disperse chromatin 

 granules are found principally around the periphery of the 

 nucleus and even there are not sufficiently abundant to obscure 

 the linin strands (Fig. 10). During the dormant period of the 

 bean seed the scattered chromatin either enters the nucleolus or 

 becomes closely appressed to the nuclear membrane, as has been 

 previously shown (Kater, MSS.). In such nuclei there is nothing 

 15 



