618 Graham: Conocephalum conicum 



This first longitudinal wall is soon followed by a second one at 

 right angles to it, so that each one of the original cells is divided 

 into four. These two longitudinal walls are shown in cross 



fig^ 



Wh 



embryo, periclinal division takes place rapidly in the venter of the 

 archegonium, so that the wall is finally four or five layers of cells 

 in thickness, and the whole structure becomes much more massive 

 {^jigures i^ and i6\ Moreover, the tissue forming the original 

 stalk of the archegonium increases, .and its cells become rich in 

 protoplasm. Because of their deeply staining contents and their 

 smaller size, there is a strong contrast between them and the 

 adjacent tissue of the gametophore {figure jy). The whole 

 calyptra is much thicker and more massive than that of Marchantia 

 and Preissia: 



The young sporogonium next increases decidedly in length 

 {figures /p, 20, 22^ jo) and the elongating proximal end forces 

 its way into the tissue developed from the stalk of the archegonium, 

 from which it derives its nourishment (figures i6^ 22^ 28). This 

 elongated more slender proximal portion of the sporogonium is 

 the foot or absorbing organ. It is apparent, therefore, that the 

 foot in Conocephalum conicum becomes differentiated much earlier 

 in the life history of the sporophyte than in Marchantia or Preissia. 

 The mature foot is a conical structure deeply imbedded in the tissue 

 of the gametophyte, while in Marchantia and Preissia it is very 

 short and broad. 



The elongation of the embryo is accompanied by repeated 

 transverse division, so that it becomes a clavate structure, many 

 cells in length {figures 75, 26, 28, 2g), Some of the original 

 transverse walls appear heavy and prominent at this stage {figures 

 ^Sy ^^* -^y ^9\ It seems certain that one of the original four or 

 five transverse walls formed in the embryo separates the capsule 

 primordium from the stalk and foot portion, but w^hether this is the 

 first original wall cannot be stated positively. Figure 2g shows a 

 sHghdy older stage in w^hich one of the original walls is distinct. 



Growth is now more rapid in the distal or capsular portion of 

 the sporogonium. By the formation of periclinal and transverse 

 walls it increases in breadth and massiveness (figures 21, 26, 28, 



