(124) 



serratus and vesiculosus abound ; these plants it peculiarly affects, but is also 

 occasionally observed on F. iiodosus, and perhaps on other allied species. 

 It forms very conspicuous brush-like tufts on the plants which it infests, 

 often in such abundance as to give it quite a shaggy looking aspect. 



The tubercle is said to originate under the surface of the plant, and 

 is by some considered the most essential part of the frond, as containing 

 the fructification ; the long, slender filaments that form the brush-like 

 portion, and the most conspicuous part, being considered as merely 

 accessory. Both, however, appear to have much the same structure, 

 and to be similarly coloured. The elongated filaments, although not 

 perhaps absolutely essential to the fructification, are very different from 

 the colourless hyaline filaments so common on the marine Algse. 



The large size of the present species, the i-epeatedly dichotomous fila- 

 ments of the tubercle, and the long, slender, attenuated filaments of the 

 brush, will readily distinguish this from the other species of the genus. 





KLACHISTA FUCICOLA. 



EXPLANATION OP DISSECTIONS, &c. 



Fig. 1. — Elachista fucicola, on Fucus vesicvlosus, natural size. 

 2. — Filaments. 



3. — Apical filaments (paranemata). 

 4. — Portion of a filament. 

 5. — Spores. All magnified. 



