88 



that Griff ithsia Borne ti ana needs some other substra,tuin 

 than the stones on v.hich tlie inatwe plant is often found, 

 to pass tl'irough the early staces of its eristdnce. 



When the sporeling is growing on some other alga, the 

 "basal cell mav simply hecoiie attached to the surface ■by- 

 some adhesive at the surface of contact (fig. 164), or may 

 grov/ in betv/een the cells of the s.lgal substratum (fig. 165) 

 or may even tv/ine about it in the ma.nner of the rhizoidal 

 tendrils, 



Further development of tlie basal cell results in its 

 division into cells of various sizes and irregular shape. 

 Usually short tubular projections resenbling rhizoids, be- 

 come cut off (figs. 170,171) by the circular ingrov;th of 

 the cell v/all , Somewhat less frequently dome-shaped seg- 

 ments are formed on. the sides of the basal cell (fig. 172). 

 In either case a multinucleate lioldfast, or attaching disk 

 is formed, all the cells of \/hich are derived from the di- 

 vision of the ba.sel cell. 



The apical cell cuts off daughter segments ir; the 

 usual manner (fig. 1'^^) . By the time tlie sporeling is 

 four or five cells long, lateral branches appear on the 

 upper borders of the cells below tlie apex (fig. 175) . The 

 rapid grov/th of the lateral branches gives the characterist- 



