262 IP 5 t e I 5 t a 



thickening discernable in the walls of the inner 

 cortical cells. 



Holdfast. The holdfast is made up of 

 thin walled cells continuous with the cortex 

 of the sti])e. They are arranged in radial lines 

 centering in the base of the center of the hold- 

 fast, i. e. tlie original jjosition of the primitive 

 disc. Into this mass of cortical tissue extends 

 the cylinder of pith from above, which gradually 

 narrows and vanishes downwards. As described 

 above, regions of local increase in thickness 

 are often present. Sometimes this local growth 

 may even be so active as to give rise to a branch 

 which grows out from the main disc but is so 

 closely a])i)ressed to it as to be unnoticeable 

 exce})! in section. (Plate TIL, figs. 2,3). 



The lamina (Plate III., fig. i) being thinner 

 than in most of the kelps, is but a few (14-18) 

 cells thick. The pith-web is extremely thin and 

 there is no sclerenchyma. In the fruiting area 

 nothing unusual was ol^served. 



Habitat. KcjijrciLia parviila grows in the 

 sublitoral zone in the tide pools and recesses 

 never uncovered even at the lowest tides. It 



