THE HIGHER CRYPTOGAMIA. 299 



and parallel to the Avails of the central cell. In consequence 

 of these divisions the central cell of the archegonium, when 

 fully developed, appears to be surrounded by one or two 

 epithelioid layers of cells (PL XXXVIII, figs. 14). 



Inside the central cell, during the first stage of develop- 

 ment of the archegonium, there is formed a daughter-cell, 

 the germinal vesicle. It originates round a secondary 

 nucleus, which makes its appearance in the apical arch of 

 the cell (PI. XXXVII, figs. 35, 36), sometimes as early as 

 the commencement of the formation of the transverse 

 septa of the two pairs of cells which form the neck of the 

 archegonium (PI. XXXVII, fig. 35). It grows gradually, 

 and during the formation of the archegonium displaces 

 more and more the contents of the central cell, especially 

 the second nucleus of the latter, which exists during its 

 formation (PI. XXXVIII, fig. 1). When the archegonium 

 opens, some granular mucilage, the last remnants of so 

 much of the contents of the central cell as has not been 

 absorbed in the formation of the germinal vesicle, seems to 

 be usually spread over the outer wall of the free spherical 

 cell (PI. XXXVIII, fig. 2). 



The four longitudinal rows of cells which form the neck 

 of the archegonium now become disconnected at their edges. 

 An open canal is formed leading to the central cell and 

 traversing the longitudinal axis of the cylindrical neck. 

 This canal is the entrance to the archegonium. The four 

 elongated cells of its mouth bend semicircularly backwards 

 by which means the archegonium assumes a very strange 

 appearance ; it resembles an anchor with four flukes or arms 

 (PL XXXVIII, figs. 2, 3, 4, 6). The arched cells of the 

 mouth when they part asunder contain no solid matter ; the 

 few chlorophyll vesicles as well as the nucleus of the cell 

 have disappeared. The same is the case with the four cells 

 which support those last mentioned. The free neck of the 

 archegonium is transparent like glass. 



There is far less difference between the structure of the 

 archegonia of the Equisetaceae and those of ferns than there 

 is between the antheridia of the same plants. The former 

 agree in all essential features with those archegonia of the 

 Polypocliacese in which the neck consists only of four longi- 



