I III GAMETOPHYT1 



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angles to the primary division wall. I he next divisions are, usually al least, anti- 

 clinals (Hg. 97, G), but before long the periclinal walls also are developed and sub- 

 sequent divisions do not show any recognizable regularity in their sequence; there 

 seems to be a good deal ot variation in this respect, even in the same species. The 

 number of cells ultimately formed varies a good deal, but the number of spermato- 

 cytes finally developed is probably never so great as that found in some of the 

 ( )phioglossaceae. Kaulfussia, both in the size of the antheridium and thai of the 

 spermatozoids, approaches nearest to Ophioglossum. I he number of spermatozoids 

 may reach several hundred, fifty or more being visible in a single section of a large 

 antheridium, and nearly or quite as many may sometimes be found in Dancea, 

 where, however, the spermatozoids are much smaller than in Kaulfussia. 



In the cover cell the divisions are all anticlinal and horizontal sections or 

 surface views show that the successive walls are arranged spirally in a way suggesting 

 the segmentation of a three-sided apical cell. The last-formed wall cuts out a small, 

 nearly triangular cell, the opercular cell (fig. 95 D, E, 0). In most cases, at least. 



Fie. yv. 



Ripe antheridium of /). jamaicensis. m, mantle nils. A. Transverse section of three jroung antheridia of D.jamaici ■ i 

 0, opercular cell. X350. B. Surface view of the two youngest ones, a, opercular cell. X380. 



this opercular cell Js thrown off when the antheridium opens, leaving a small 

 aperture through which the spermatozoids are ejected. Surrounding the mass of 

 spermatocytes is a layerof mantle cells cut off from the adjacent cells of the prothal- 

 lium. These mantle cells, at the time of the opening of the antheridium, become 

 very much distended and project strongly into the cavity of the empty antheridium 

 (fig. 100, /?, m). They no doubt play an important part in the dehiscence ol tin ripe 

 antheridium. 



SPERM \ loci, \ |s|s. (Plate :, figs ^-44.) 



Of the Marattiaceas, Kaulfussia is the most satisfactory foi studying the details 

 of spermatogenesis, owing to the much larger size ot the spermatozoid. I he 

 development of the spermatozoids agrees very closely in its details with that of 

 Ophioglossum. If the spermatocyte is examined just before the final division the 

 two blepharoplasts can be seen and the division of the cell into the two spermatocytes 

 proceeds very much as in Ophioglossum. After the final division the nucleus ot the 

 spermatocyte appears coarsely granular ami, as in other cases, no nucleolus can In- 

 seen. In favorable cases the blepharoplast is visible as a round body, stained 



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