82< 



ceedinE division. At about this time, the sporeling 

 changes its shape, pusliing out, at the point of attachment, 

 a small rounded projection, (fig. 158) i.liich later becomes 

 cut off as the basal cell. Iminediately after this projec- 

 tion is formed, tlie spoi^eling elongates, becoming about 

 t\dce as long as broad, but witiiout undergoing cell divis- 

 ion (fig. 159) . 



As these changes take place, the cytoplasm migrates 

 more c:n6. more to the periiihery. Tlie central part of the 

 sporeling is occupied by sm&,ll regular vacuoles, \.hose ex- 

 ceedingly thin walls are rouglily hexagonal in secfeio.M (fig. 

 160). A single large central vacuole such as is character- 

 istic of the vegetative cells of the older plants is not 

 usually foi^med until the sporeling reaches the 3-celled 

 stage. 



Cell division occurs usually wiien aboprt 16 nuclei are 

 present. A v/all at right angles to the long axis of the 

 spoi^eling cuts off a small basal from a large aidcal cell 

 (fig. 161), Shortly after this, without further elongation 

 of the sporeling, tjie ti] ica.l cell divides into two by a 

 wall parallel with the first (fig. 162). The details of 

 the formf.tion of these walls v/ere not follov/ed out. As 

 the partitions have not been seen to assume the arched 



