8 HOFMEISTER, ON 



cell-cavity. In the hemispherical cell which is thus pro- 

 duced there commences, either immediately (Plate III, 

 figs. 10, 17) or after the occurrence of one or two divisions 

 of the same cell by means of horizontal septa, a series of 

 repeated divisions of the apical cell, by means of septa in- 

 clined in opposite directions. The cells of the second 

 order which are thus formed are bisected by the growth of 

 radial longitudinal septa (PL III, fig. 18). There is thus 

 produced a short clavate mass of cellular tissue, composed 

 of four parallel longitudinal rows of cells. One of the cells 

 of the double pair of cells adjoining its apex divides by a 

 septum which, lying parallel to the longitudinal axis of the 

 organ, forms with the side walls of the mother- cell an 

 angle of 45°. Thus arises an inner cell which is sur- 

 rounded on all sides by a simple cellular layer. The inner 

 cell expands at the expense of the surrounding cells, the 

 latter becoming tabular and flattened. These cells hence- 

 forth multiply only by divisions produced by septa perpen- 

 dicular to the free outer walls. It is probable that the 

 number of the cells of the cortical tissue of the antheridia 

 increases, but such tissue always consists of a single layer 

 of cells. The inner cell, on the contrary, becomes converted, 

 by means of a series of continued bisections, into a multi- 

 cellular body, the cells of which become smaller in pro- 

 portion as their number increases (PL III, figs. 19, 20). 

 In its latest stage of development, this cellular body is a 

 spheroidal mass of very small, almost tabular cells (PL III, 

 fig. 21). Each of them contains a lenticular vesicle which 

 almost fills the cell. The walls of the cells decay as the 

 antheridia approach maturity. In the meantime, in each 

 of the vesicles, a delicate helicoid filament of from two to 

 three and a half turns., and composed of a substance which 

 is coloured yellowish by iodine (PL III, fig. 22), forms 

 itself into an antherozoid. At this period the cellular layer 

 which covers the cavities in the cellular tissue of the frond, 

 and which cavities are almost filled with antheridia, bursts 

 irregularly. It often happens that in the mean time the 

 chlorophyll-bodies have assumed a reddish-yellow colour. 

 The same colour appears regularly and with increased in- 

 tensity, at the approach of maturity, in the colouring par- 



