THE GAMETOPHYTE 



133 



The archegonium in Dancea, while resembling that of the other Marattiacese, 

 in its position and early development shows some marked differences, the signifi- 

 cance of which is not quite clear. The division of the mother cell into the primary 

 neck cell and the central cell follows in the same way as in the other forms, but the 

 inner cell, usually at least, does not have a basal cell separated from it, but develops 

 at once into the egg cell and canal cells. The absence of the basal cell is by no means 

 unknown, however, among the other Marattiaceje. The primary neck cell gives 

 rise to the usual four cells, each of which divides into three or four, and exception- 

 ally into five. There is a marked elongation of the inner cell before its separation 

 into the central cell and the neck canal cell (fig. 103, D). 



Fig. 104. 

 A, young, B, nearly mature, archegonium of D.jamaicensis. X360. 

 C, D, cross-section of a young archegonium of same species. D shows the four primary neck cells. 



Up to this point there is nothing peculiar in the development of the archegonium 

 in Dancea, but while in most of the other Marattiaceae a conspicuous ventral canal 

 cell is formed, its sister cell being the egg, in Dancea the formation of a definite 

 ventral canal cell could not be satisfactorily demonstrated. In a number of cases 

 (fig. 105; plate 2, fig. 45) a small nucleus-like body could be seen in a large, clear 



Fig. 105. 

 Three mature archegonia of Dancea elliptica. X350. 

 A and B show traces of a ventral canal cell ; f, in B, a division of the neck canal cell. 



space just above the somewhat contracted mass of protoplasm, with its large and 

 conspicuous nucleus, which constitutes the egg cell; but this ventral canal cell 

 nucleus, if such it is, is very different in appearance from the large and conspicuous 

 one found in the other Marattiaceae, and in the absence of any division stages its 

 nuclear nature must for the present remain somewhat doubtful. 



There is somewhat the same uncertainty in regard to the primary division of the 

 neck canal cell. This possesses a large and conspicuous nucleus which in large and 

 apparently mature archegonia was still undivided. In a few cases a division of the 

 protoplasm in the neck cells was observed; in other cases, without any such division. 



