368 HISTORY OF BRITISH ZOOPHYTES. 
summon the Dryads, and convert them into a marine band 
of Nereids, there might, from groves of tangle, burst forth 
music, . 
“ Like harp Aolian’s sweet aerial notes.” 
The height of the polypidom is an inch and upwards, 
dichotomously divided; cells numerous. 
Genus XXIV. VESICULARIA, J. V. Thompson. 
Gen. Char. Polypidom rooted, confervoid, fistular, horny, di- 
chotomously branched, jointed at the divisions: cells ovate, dis- 
junct, uniserial and unilateral. 7 
1. VEsICULARIA SPINOSA, Silk Coralline, Did/enius. (Plate 
XX. fig. 77.) 
Hab. On oyster-beds, Dr. Fleming; shores of Ireland, 
W. Thompson ; Mersey, Mr. Tudor ; Leith shore, D. L., jun. 
This, from its fineness, has been called Sea-silk Coral- 
line: the stem is formed by fine silken threads, united, and 
the ramifications arise from this with a zigzag stalk. In 
the small branches appear rows of holes with a rim, as if 
bored from within outwards. ‘The vesicles are of an oval 
shape, and open at the top. ‘They are so delicate that they 
can with difficulty be seen; but when they are seen, they 
