VI.] STONEWORTS. 51 



y. The structure of these threads; each consists 

 of a single row of cells, containing in unripe 

 specimens nucleated protoplasm ; in older spe- 

 cimens each contains a coiled-up antherozooid. 



b. The anther ozooids. 



a. Their form and structure ; thickened at one 

 end and granular ; tapering off gradually to- 

 wards the other end which is hyaline, and has 

 two long cilia attached to it. 



/3. The movements in water of ripe anthero- 

 zooids. 



[Sometimes Chara cannot be obtained, when Nitella, 

 another genus of the same natural order, and of similar 

 habit and structure, can. Nearly all the points above 

 described for Chara can be made out in Nitella, with 

 the following differences : the cortical cells of the stem 

 and leaves are absent, and, in the commoner species, 

 the plant is not hardened by calcareous deposit ; the 

 branches arise, not one from a whorl of leaves, but two ; 

 and the five twisted cells of the spore-fruit are each 

 capped by two small cells, instead of one.] 



C. PROTOPLASMIC MOVEMENTS IN VEGETABLE CELLS. 



a. Chara. Take a vigorous-looking fresh Chara or 

 Nitella-cell (say the terminal cell of a leaf), and 

 examine it in water with a high power. Note 

 the superficial layer of protoplasm in which the 

 chlorophyll lies ; it is stationary : focus through 

 this layer and examine the deeper one; note 

 the currents in it, marked by the granules they 

 carry along: their direction; in the long axis 

 of the cell, up one side and down the other, 

 the boundary of the two currents being marked 



