186 UTRICULAR STRUCTURES. 



form, and through this same pressure adhere together as 

 a tissue (fig. 12 g). If the utricle then becomes absorbed, 

 the grains either remain united in a group (fig. 12 n) or 

 separate. Since, however, they have acquired a solid 

 structure by the formation of layers of lignification, they 

 do not reassume the globular form, but remain polygonal 

 and exhibit a shape which has a crystalline appearance, 

 without, on that account, being actually crystals (fig, 14). 



I do not mean, however, that the starch-grains which 

 have originated together in the same utricle, necessarily 

 always assume a parenchymatous shape ; they only do 

 this when they are contained in proportionate number or 

 size (to the size of the utricle). If they lie more loosely 

 in the utricle, they always remain isolated and retain their 

 rounded surface. Thus I have never seen starch- grains 

 become properly parenchymatous, either in the nuclear 

 or prolific utricles. In the green utricles, also, I have 

 likewise often seen them remain globular, even when a 

 number have originated together in one utricle. 



Those starch-grains, therefore, which lie separate and 

 are bounded by a single curved surface, have originated 

 either free in the cell, isolated in utricles, or in numbers 

 loosely arranged in utricles. Those which lie separate 

 and have one or more plane surfaces or angles, have 

 originated in numbers, closely packed in a green utricle. 



In like manner the granules united into a mass have 

 been formed together in a green utricle. 



The original contents of the starch-utricles are unknown. 

 As soon as they have attained a sufficient size to allow of 

 their being investigated, they are coloured blue, violet, or 

 red, by iodine. The formation of layers, therefore, begins 

 very early, and it must thence be assumed that the outer- 

 most and first layers expand considerably in surface until 

 the growth of the utricle is completed. There is nothing 

 whatever opposed to this hypothesis, since the layers are 

 at first in a soft, semifluid condition, and since the cell- 

 membranes and the earliest of its layers of thickening are 

 likewise capable of considerable expansion. 



Consequently starch -utricles and cells agree in this: that 



