CHROMOSOMES 235 



their appearance immediately before the process of 

 division, are found with their extremities situated in 

 little pockets or bulgings of the nuclear membrane, 

 so that their exact position is very definitely marked ; 

 and the arrangement of the chromosomes may be any 

 one of those already indicated. Boveri observed that 



-3V 



FIG. 27. FIG. 28. FIG. 29. 



in the case of two neighbouring cells which had 

 originated by the division of the same mother-cell, the 

 chromosomes made their appearance in both cases in 

 the uncommon position of Fig. 29. Figs. 30 and 31 

 indicate their actual arrangement. The conclusion to 

 be drawn from this observation is that the same 



FIG. 30. FIG. 31. 



chromosomes have preserved their individuality right 

 through the resting stage of the nucleus, to reappear 

 in the same position at the outset of a new phase of 

 division. 



It is believed, then, that the same stages which the 

 chromosomes passed through at the close of one 



