M. filiformis is much the most abundant species, and is, 

 indeed, very generally to be found clothing the Chorda, when the 

 latter grows in small shallow pools, exposed to strong sunlight. 

 In such localities almost everv frond of Chorda lomentaria is 

 converted into a soft, cylindrical brush, from the multitudes of 

 these little parasites, clothed with their gelatinous, transparent 

 hairs, which, while the plant remains in the water, stand out on 

 every side, keeping each little filament free of its neighbour. 

 When drawn into the air, the whole falls together in a gelatinous 

 mass. 



In the list of British Algae given at the conclusion of our first 

 volume, the names Ectocarpus simplex, Ag\, and E. villum, Harv., 

 occur. Since that list was printed I have made a more careful 

 examination of the specimens on which these names were im- 

 posed, and fear that both are referable to young states of M. 

 filiformis. Never having seen an authentic specimen of Agardh's 

 E. simplex, I cannot take it upon me to pronounce his plant to 

 be identical with the Jersey plant so named by me ; but judging 

 from the description given, by that author, I think it very pro- 

 bable that his plant is the same as ours, and therefore to be 

 regarded as a synonyme of M. filiformis. In strict priority, should 

 this opinion be established, the specific name " simplex " would 

 belong to our present species, but as this word denotes a cha- 

 racter common to the genus, it seems undesirable to adopt it for 

 a species. 



Pig. 1. A plant of Chorda lomentaria infested with Myriotrichia filiformis : 

 — of Ike natural size. 2. Fronds of the latter : — magnified. 3. Small por- 

 tion of a frond — highly magnified. 



