206 Dr. H. Karsten on the Sexual Life of 



ing cell-layer (the archegonium) becomes thicker and opake 

 and conceals the enclosed cells. 



Moreover the branches surrounding the archegonium as far 

 as its apex ramify still more, particularly about the base, and 

 attach the enlarging archegonium so much the more firmly to 

 the parent branch as well as to other branches adjoining, and 

 constitute for it an outer cortical layer (figs. 2 & 5 a, strongly 

 compressed). 



In thin longitudinal sections which contain the central tissue 

 of the young archegonium, the centre may be seen entirely filled, 

 for some time after the act of impregnation, with large, thin- 

 walled cells, united in groups of four, containing a cloudy, 

 gelatine-like matter. Some of these cells present no definitely 

 formed corpuscles, whilst others (fig. 4) contain small granules 

 and vesicles, but in no considerable quantity. By tearing and 

 pressing the section under water, these collections of four ad- 

 herent cells can be isolated. 



Similar sections of archegonia of rather larger size show 

 these large delicate cells, developed from the one central free 

 cell of the archegonium, to be completely filled (fig. 3) with 

 little ellipsoidal corpuscles, derived no doubt by an act of multi- 

 plication of the vesicles previously formed in the phase of de- 

 velopment above described. 



Longitudinal sections of still older but as yet closed arche- 

 gonia (fig. 11), before they have become gorged with water, still 

 display a central granular mass and groups of cells, from which 

 the central tissue is progressively formed. When the section is 

 thoroughly filled with absorbed fluid, this central tissue exhibits 

 a homogeneous ellipsoidal mass, flattened at its two extremities ; 

 and whilst its base is enveloped by a cup-shaped lamina (derived 

 from the modified cells of the archegonium) which is rather less 

 porous than the cortical layer that surrounds the whole, its 

 apex seems to be covered by large cells. The latter can no 

 longer be detached. On tearing the preparation longitudinally, 

 we ascertain that the large cells of the centre are conjoined with 

 the adjacent layer of tissue, and that their apparently granular 

 contents consist of long cylindrical cells, attached to the peri- 

 pheral tissue, but free towards the centre. 



These fibres are transitional forms in the development of 

 spores and paraphyses ; they have a mucilaginous appearance, are 

 not quite uniformly cylindrical, but rather moniliforin (fig. 13), 

 as if the rudimentary spores were disposed in longitudinal rows 

 next each other. 



Moreover the archegonial cells (matrix) are now fibrous in 

 form, like those of the cortical tissue, and are scarcely at all 

 separable from the latter, or from the tubular layer, without 



