1 1 1 1 — I 1 1 — r- 



12 24 36 48 



-I — I — I — I I r" 



60 72 84 96 Hours 



Fig. 2o8 Loss in weight of Fucoids in relation to time of desicca- 

 tion. The higher an alga grows the slower it loses water and the 

 greater the total loss. Symbols the same as in Fig. 202. (After 



Zanefeld.) 



Table 15 

 Fat content of some littoral fucoids 



Ether extracted 



Pelvetia canaliculata 



Ascophyllum nodosum (mid-littoral) 



Fucus vesiculosusi 



Halidrys siliquosa Hlow littoral) 



Himanthalia lorea^ 



Laminaria digitata (sub-littoral) 



This fat is largely contained in the cell walls and examination has 

 shown that the thickness of the cell wall does bear a relation to the 

 height at which an alga grows. 



Table 16 

 Thickness of some Fucoid cell walls 



Thickness in divs. of 

 3^ 



Fucus spiralis var. platycarpus 

 Ascophyllum nodosum 

 Fucus vesiculosus 

 Fucus serratus 



388 



o-49±o-05 

 034 ±001 

 0-23 ±003 

 0-14 ±001 



