*PHAOPHYCEA 119 
The unilocular sporangia occur (Pylaiella) in rows 
of intercalary cells or (Jsthmoplea, Ectocarpus, &c.) 
as lateral outgrowths of the cells, generally sessile, 
and oval or globular in form. 
The relationship of the order is undoubtedly a 
close one with Sphacelariacew and other orders here 
placed near it, but facts briefly alluded to above 
compel one to look to orders like Tilopteridacece for 
other marks of near alliance. 
The Geographical Distribution of this large order 
is fairly general, but is most markedly abundant in 
the North Atlantic—though this probably means no 
more than that it has been most studied here. Stred- 
lonema, Ectocarpus (many species), Isthmoplea, Pylat- 
ella, Sorocarpus, Ascocyclus occur in British seas. 
