THE HIGHER CRYPTOGAMIA. 11 



a septum cutting one of its sides, and parallel to one of 

 its other sides ; and partly the form of a three-sided prism, 

 so far as they originate from the division of the apical cell 

 by a septum parallel to one of its short side-walls. Seen 

 from above, the apical cell has an oblong form (PI. I, fig. 25); 

 in a longitudinal section, it is triangular if the section is per- 

 pendicular to the long side-walls (PL I, figs. 21 "' c ' 23 h ), 

 quadrangular, on the other hand, if the section is at right 

 angles to the shorter side-walls (PI. T, figs. 21 d ' 23 "). 

 Each cell of the second degree divides, soon after its pro- 

 duction, into an inner and an outer cell, by means of a 

 septum parallel to the chord of the arc of the free outer 

 surface. Each of the latter cells is divided by a longitu- 

 dinal septum radiating from the longitudinal axis of the 

 fruit ; those cells adjoining to the side faces of the apical 

 cell being divided at an earlier period, and more repeatedly, 

 than those adjoining the terminal faces (PI. I, fig. 23). 

 These divisions take place in such a manner that the cell 

 is divided into two portions of unequal size, of which the 

 larger portion immediately divides again by a septum 

 parallel to the septum last formed. Further longitudinal 

 divisions take place (especially in the side cells of the 

 mass of cells which is formed by the multiplication of a 

 single cell of the second degree), in such a manner that, 

 measured in a tangential direction, their number appears 

 to be represented by the odd numbers, 3, 5, 7, &c. 

 (PI. I, fig. 25). The division of those cells of the outer 

 surface of the fruit which immediately adjoin the apical 

 cell (which division takes place by a radial longitudinal 

 septum) is shortly followed by the formation of a trans- 

 verse septum, also perpendicular to the free outer surface, 

 but at right angles to the septum just mentioned. In 

 the cells which originate from the smaller cells of the 

 second degeee, the formation of the transverse septum 

 often precedes that of the longitudinal one (PL I, fig. 25). 



In the rudimentary fruit of Anthoceros, as in other 

 growing organs, one step in the regular series of cell- 

 divisions is often anticipated. It sometimes happens that 

 a division takes place before the occurrence of another divi- 

 sion which usually follows it, and yet the final arrangement 



