Dostetsta 201 
of that of the present species and only a few 
features need be considered. As far as it goes 
the histology bears out the gross anatomy in 
indicating a primitive position for the present 
species. 
STIPE. The pith-web is much simpler than 
that of most of the kelps. It is made up of 
anastomosing hyphe as is usual; but they are 
shorter, composed of shorter cells, with less 
mucilaginous matrix between them than most 
species, e. g. Laminaria bongardiana which 
was studied for comparison. These hyphe are 
sometimes so poorly developed that in both 
cross and longitudinal sections (Plate II.) of 
the stipe the pith appears to be composed of 
small spherical cells with only a few longer 
hyphe, contrasting strongly with Laminaria 
whose stipes show very many long hyphe and 
but few round openings where others have 
been cut across. The development of thick 
walled supporting tissue (sclerenchyma) from 
the cortex is also less marked in Renjrewia 
than in most kelps though there is some varia- 
HOM sin) this Tespect. “Sometimes, tere 1S no 
