152 HISTORY OF BRITISH ZOOPHYTES. 
14. SeRTuLaRia FILICULA, Fern Coralline, Hudson. (Plate 
Nemo.) 
Hab. On seaweeds, especially on the entangled roots of 
Laminaria digitata ; Mr. W. Thompson states that it seems 
to be partial to bivalve shells on the coast of Ireland, and it 
is also found on Flustra. Itis rare in the west of Scotland, 
and is seldom found except at the roots of LZ. digitata. It 
is not common anywhere, though it is widely distributed. 
“ Height about an inch; branches alternate; cells wide 
at the base, contracted towards the orifice, which is slightly 
tubular, with a wrinkle or depression, forming a shoulder on 
the upper side; vesicles ovate with a narrow base, and a con- 
tracted subtubular orifice.” (Dr. Fleming.) “ It sometimes 
rises to the height of four inches; the stem has a zigzag 
appearance ; the cells are shaped like a Florence flask. The 
vesicles are represented by Ells as pear-shaped, but they are 
very seldom seen. ‘The singularity of its waved stem, with 
its erect, single, axillary cell at the insertion of the branches, 
together with the single pair of cells on each part of the 
stem that form the angles, make it a very distinct species 
from any of this genus.” (Z/iis.) 
Though it bears some resemblance to a young specimen 
of S. abietina, it may be easily distinguished, as Ellis has 
