1920] HAUPT—FOSSOMBRONIA 327 



are conspicuous in the cytoplasm (fig, 33). The egg protoplast 

 does not lay down a new wall until after fertilization. More than 



m in 



urn is of an advanced typ 



development from the initial, its relatively fe 

 its inactive cover cell, the intercalary growth 



and its slender venter. 



Sporophyte 



The first division of the fertilized egg is invariably transverse, 

 and is followed by transverse divisions up to 5-7, the sequence of 

 which could not be determined (figs. 34-36). A vertical wall 

 then appears, intersecting the transverse walls (fig. 37), and 

 followed by another vertical wall at right angles to the first one, 

 so that 4 cells are seen in cross-section. Periclinal walls then 

 appear in the upper part of the embryo and a sterile wall is thereby 

 cut off from the central primary sporogenous cells. The relation 

 of the early divisions of the embryo to the formation of the foot, 



determined 



development 



sporophyte, not merely forming an appendage to the foot, 

 mder calyptra 3 or 4 cells in thickness is formed from the venter 

 le archeeonium (figs, ^q, 18). A simple, bell-shaped involucre 



develops after fertilization; 

 length (fig. 45). 



in 



in the history 



the sporophyte. In the formation of the spore mother cells and 

 elaters, the protoplasts of the sporogenous tissue withdraw from 

 their cell walls (fig. 39), those which are to form spores round out, 

 and both the spore mother cells and young elaters form a new 

 wall as the original walls of the sporogenous mass are dissolved 

 (fig. 40). The spore mother cells and young elaters are derived 

 from the sporogenous cells by the same number of cell divisions. 

 In F. cristida an elater is not homologous with a row of spore 

 mother cells, as in forms with a more highly specialized sporophyte, 

 but with a single spore mother cell. The spore mother cells 

 develop 4 inconspicuous lobes (fig. 42), the reduction divisions 



