100 



Those arriving at early maturity are the little cells, c, in the pri- 

 mary tubes, the globular clusters, g, under each knot, the cells, h, on 

 the arms, and the terminal cells, i. 



The covered cells having green vesicles in motion, in the knots 

 and in the joints of the arms, form the second class. 



The third class of cells having a flexible mass or cytoblast sliding 

 round, are the primary tubes, a, b, b, the central tubes of the arms, j,j, 

 the nine stalks in the globule, and the fourth cell in the bottom of 

 the seed. In these the circulation is vigorous. 



Those of the fourth class are the secondary tubes, e,/, around the 

 stem, the tubes, k, I, which cover the arms, the tubes around the seed 

 and the sprouts amongst which the seed grows, and generally all the 

 terminal cells. In these the circulation is slower, and often requires 

 a high power to see it. 



The roots have a flexible vesicle, which becomes lodged just under 

 the surface of the matter deposited in their lower ends. This is shown 

 at o, figs. 5 and 27. 



Whilst writing this, a seedling under the microscope appeared 

 beautifully transparent, had many distinct forms of different shapes 

 and sizes in the main stem, but no flexible vesicle gliding along. 



Fig. 25* is a section of the main stem,* without its covering-tubes, 

 to show the spiral indents, p, p, to which the lining adheres : they 

 mark the boundary between the ascending and descending currents. 



Fig. 26. A portion of stem out of which the lining was floated : 

 it came out in two portions, q, q, being rent at the line of adhesion. 

 From the Nitella the lining will float out whole, as shown in fig. 26*, 

 at q, q. 



Fig. 27 is an edge-view of a portion of the lining of Nitella trans- 

 lucens, magnified 700 times. The studs which pave the lining are 

 oval whilst living, but when taken out they become round, and the 

 lining shrinks. These studs have other distinct green vesicles within 

 them, various in number, as at v, v. There was a very singular addi- 

 tion to this lining, both on the outside and inside, namely, the 

 clear, thin, globular masses, w y w. They were extraordinary from 



* Any ordinary cutting to obtain sections would squeeze the tube flat, and spoil 

 it and the lining, so I took advantage of the fact, that water, when struck quickly, 

 resists like a solid, and therefore laid the Chara on smooth wood, just covered with 

 water, then, with a sharp knife, made suddenly a number of quick cuts across it, and 

 so obtained the various sections required. Wet a slip of glass and turn the wood 

 over so as just to touch the water, and the sections will fall from the wood on the 

 glass, and thus be ready for the microscope. 



