BoT.— Vol. II.] 



OSTERHOUT—A GA VE. 265 



at the same time losing its capacity for staining violet. 

 After it has entirely disappeared, the granules remain intact 

 for some time, and then disappear in turn. The dissolution 

 of the wall begins beneath one of the cones ; the wall then 

 breaks down under the others, and the process slowly 

 extends from these points until the wall has completely 

 disappeared (see figs. 10 and 11). 



The development of linin fibres keeps pace with that of 

 the genetic fibres, and at the disappearance of the nuclear 

 wall these fibres are quite numerous (see fig. 10). 



Usually the spindle wall begins about this time to fray 

 out more or less into free fibres and lose its membranous 

 character. This disintegration of the spindle wall occurs 

 sometimes earlier, sometimes later, and is decidedly variable 

 as regards the time of its commencement. 

 3. Stellar Stage. 



With the disappearance of the nuclear wall, and the com- 

 plete development of the cones, the genetic stage may be 

 considered to end. In the next stage the spindle has a star- 

 shaped appearance, due to the irregular position of the 

 cones; this stage will therefore be called the stellar stage; 

 it may be defined as lasting from the end of the genetic 

 stage to the time when the cones are separated into two 

 groups and the fibres begin to take on a parallel arrange- 

 ment. From this time on the spindles resemble fasces, and 

 this stage will accordingly be called i\iQ fascicular stage; it 

 may be considered to end with the fusion of the cones to 

 form the bipolar spindle, or, in cases where this does not 

 occur, with the arrival of the daughter chromosomes at the 



poles. 



In Agave the beginning of the stellar stage is marked (in 

 the pollen-mother-cells) by the penetration of the genetic 

 fibres into the nuclear cavity (figs. 10 and 11), where they 

 soon become mingled with the linin fibres. The number of 

 poles is usually, at this time, from three to eight. 



The chromosomes retain their original arrangement for 

 some time after the disappearance of the nuclear wall (fig. 12) , 



