the expanded fronds of Lam. digitata, where it often fringes the 

 segments in continuous tufts, but it is not confined to that plant, 

 but is commonly found also on L. bullosa and on Himanthalia 

 lorea, and others of the larger fucoid Algae. When young and 

 well grown it is a very handsome species, but soon becomes 

 coarse and ropy, and towards the close of the season is very much 

 infested with Biatomaceous parasites. 



I have received numerous specimens from correspondents in 

 North America, in which country this would appear to be one 

 of the most abundant of the genus. 



The silicules are generally strictly sessile, but vary in form 

 from linear-subulate to nearly ovate-acute. 



Fig. 1. Ectocarpus fasciculatus : — the natural size. 2. Branch with fasci- 

 culate ramuli. 3. Branchlet with silicules : — both magnified. 



