134 MR. HENFREY ON THE DEVELOPMENT 



simple structure described by Suminski and Wigand, consisting of a simple cell; this 

 statement is quite contrary to my observations ; I frequently examined antheridia in all 

 stages in such prothallia, and they differed from the normal form only, in certain cases, 

 by being supported on elongated pedicels produced by an unusual growth of their basal 

 cells (fig. 50). With regard to the mode of development of the sperm-cells, Hofmeister de- 

 scribes, as I have done, the gradual subdivision of the mucilaginous contents of the parent- 

 cell into numerous cubical portions, each of which becomes clothed with a membrane and 

 produces a spermatozoid within it. His description of the spermatozoids differs but little 

 from mine ; he asserts, however, the regular existence of a long and very slender hair-like 

 process at the hinder extremity, which I have only seen an indication of in one case. 



In his account of the development of the archegonium he differs considerably both from 

 Mettenius and myself, although the final results are the same. According to him, the 

 papillar process is formed before the basal cavity (the embryo-sac), by the growth out- 

 wards and subdivision of one of the superficial cells of the cushion-like thickening of the 

 prothallium. He describes the formation of the archegonium in the following manner : 

 the superficial cell which gives origin to it becomes divided by an oblique wall into an 

 upper and a lower cell, the upper and larger is again divided by an oblique wall inclined 

 in the opposite direction, and this is repeated five or six times ; this would result in the 

 formation of a papilla composed of two parallel rows of cells slightly overlapping alter- 

 nately as they rise ; but as they are developed each is divided into two by a perpendicular 

 radial wall, so that the papilla consists of four conjoined vertical piles of cells. In the 

 next place, either all or only the lowest of the cells of one of the vertical rows become 

 divided into two by a tangental wall ; so that, in the first case, a central row of cells is 

 formed, running up the centre, or, in the second case, the extra cell is only formed at the 

 bottom. This lowest cell, which is the embryo-sac, becomes enlarged rapidly ; the cells of 

 the prothallium immediately surrounding it become divided by septa so as to form a kind 

 of epithelial layer around it. During this growth the canal is formed up the centre of 

 the papilla, when the fifth row of cells exists by the solution of all but the bottom one, and 

 when this extra cell is formed only at the bottom, by the separation of the contiguous 

 inner angles of the four rows, so as to form an intercellular passage. The greater part of 

 the archegonia undergo no further development after this canal opens at the apex, but the 

 membrane bounding the canal and the cavity formed by the basal cell become coloured 

 rich brown. 



"With regard to this description of the development of the archegonium, I believe it to 

 be correct so far as relates to the production of the upper part, namely the papilla, except- 

 ing in respect to the formation of the fifth row of cells, subsequently dissolved to leave the 

 canal open. But the mode of origin of the basal cell or embryo-sac is certainly contrary 

 to my observations, since I found it before the papilla had begun to be developed, and 

 surrounded at this early epoch by the so-called ' epithelial ' layer (figs. 54-57), the papilla 

 being produced by the cell lying outside it. 



Hofmeister declares in favour of the entrance of a spermatozoid into the canal of the 

 archegonium, to fertilize a little spherical cell (the embryonal vesicle) originating in the 

 basal cell or embryo-sac of the archegonium ; this cellule then begins to expand and to be 



