the time when the elongation spoken of above is just begin- 

 ning, it will be found that the -vvall of the inner or endoder- 

 mal vesicle is no longer of uniform thickness. ?ig. 9, is 

 drawn from such a section. The ectoderm covering tne bud, 

 although it is not shown in the figure, has again become 

 flattened after its temporary thickening, and is nov/ like 

 that of the stolon. ^ The figure clearly shov/s that the sto- 

 lonic partition is made up of two lamellae which are contin- 

 uous below Y/ith each other and pass over above into the walls 

 of the inner vesicle. The important change to be noted, how- 

 ever, is that the wall of the endodermal vesicle on one side, 

 the left, is getting perceptibly thinner than elsewhere, and 

 that the whole vesicle is no longer symmetrically placed in 

 reference to the stolonic partition, but is bulging out 

 slightly to the right. This is the first indication of a 

 marked change -Thich is about to take place in the internal 

 relations of the bud-rudiment. 



By a peculiar process, which may be described as a 

 transverse or rotatory growth affecting the inner vesicle, the 

 thicker wall of the right side is carried or pushed down 

 gradually until it comes to lie eventually on the ventral 

 side, that is, the side next to the stolon. 



The stolonic partition remains stationary, and the 

 displacement or shifting around of the inner vesicle takes 

 place on this as a fixed support. The process might be il- 

 lustrated by the drooping of a flower to one side on its 

 stem, although the change of position cannot be a purely 

 passive falling over of the vesicle. In Fig. 9, a small 



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