and the apices are seldom so distinctly fastigiate as im that spe- 
cies. he habitat in which (C. wvcialis occurs, affords an addi- 
tional clue. It usually frequents rocky places, growimg on the 
rock itself, or among the thin coating of sand which covers it, 
places close to the edge of low-water mark. C. danosa, on the 
contrary, is almost always found as a parasite on other Algz ; or 
else attached to pieces of wood, and to the leaves of Zostera. To 
C. arcta, our C. uncialis has much resemblance; but is a much 
smaller plant, with very much more slender filaments. 
The root-like fibres, by which the filaments are connected 
together, are common to the three species: and if these roots be 
considered a character of sufficient importance to define a genus, 
Kiitzing’s Spongiomorpha, founded on the present plant, ought 
to include the three. 
Fig. 1. Tufts of CLapopHora UNCIALIS :-—of the natural size. 2. Filaments 
bundled together :—moderately magnified. 3. Portion of a filament :— 
highly magnified. 
