THE HIGHER CRYPTOGAMIA. 323 



XLIII, fig. 6). The lenticular vesicle encloses a very thin 

 spermatozoon rolled up in three or four coils, which soon 

 exhibits a rotatory motion in the interior of the enveloping 

 cell. By rupture of the cell-wall it ultimately becomes 

 free (PL XLIII, fig. G' ; ), and moves about in the water 

 with helicoid contortions. Its fore-end, which is hardly 

 thicker than the other, carries a few oscillating cilia (PI. 

 XLIII, fig. 6, cf). I have observed the actual entrance 

 of the motile spermatozoa into the mouth of the archego- 

 nium (PL XLIII, fig. 7). 



A short time after the appearance of the spermatozoa in 

 the neighbourhood of the large germinating spore, the large 

 cell produced in the central cell of the prothallium appears 

 divided into a few cells. The arrangement of these cells 

 shows that their formation results from repeated division 

 of the mother-cell by means of septa at right angles to a 

 plane passing through the longitudinal axis of the archego- 

 nium (PI. XLIII, figs. 10, 11). The cells of the prothal- 

 lium, with the exception of the four papillate cells, multiply 

 in the mean time actively in all three directions of space, 

 especially the cells of the lower portion. Repeated divi- 

 sion also occurs in the cells of the few-celled body enclosed 

 in the prothallium, which body is the rudiment of the 

 new plant, or embryo ; and the result is, that the latter 

 soon becomes a body composed of very small cubical cells, 

 and having the form shown in PI. XLIII, figs. 12, 13. 



That end of the embryo which is turned away from the 

 cavity of the large spore, and which points obliquely up- 

 wards, soon exhibits a more active development than is 

 seen in its other parts. It is transformed into a cone which 

 becomes continually more pointed as its development pro- 

 gresses. The multiplication of the cells is caused by con- 

 tinual division of the apical cell by differently inclined septa, 

 and by the division of the cells of the second degree thus 

 produced, by radial septa, and then by septa parallel to the 

 longitudinal axis of the cone. The mode of cell-multiplica- 

 tion resembles in its essential features that of the first frond 

 of the Polypodiacese (PL XLIII, fig. 15). A similar cell- 

 multiplication, which at first, however, is very slow, takes 

 place immediately underneath the place of origin of the 



