INTRODUCTION. 
3 
valves of the common mussel, Venus striatula , Anomice, and 
many fragments of shells and stones. Ascidians of various 
kinds are studded on the roots or in close array along the 
blades; and the stellate molluscoid forms ( Botryllus and BotryL 
hides) are equally abundant. The coarse tunnels of Thelepus 
and Terebellce , the finer tubes of Sabellaria , and the white coils 
of Serpulce wind amongst the fasciculi 5 and Nereids and Lepi- 
donoti creep into every protecting crevice. Lepralice and the 
ubiquitous Membranipora pilosa cover the dull surface of the 
tangles with silvery patches, intermingled with masses of 
Alcyonium, hydroid zoophytes, and shaggy fringes of seaweed. 
On the broad blades of Laminaria saccliarina grow forests of 
Obelia geniculata , amongst which rare and curious nudi- 
branchiate mollusks still find food and shelter after their 
perilous journey. The same seaweed is streaked with the 
tough gelatinous tubes of a little phosphorescent annelid 
( Eusyllis ). 
The chief representative of the sponges in these storms is 
Halichondria panicea , though occasionally Chalina oculata is 
equally abundant. The rugged masses of the former afford a 
favourite lurking-place for Doris tuberculata , porcelain crabs, 
and Lepidonoti ; while in the general wreck it becomes 
hispid with the stiff sharp spines of the sea-mice, common and 
purple heart urchins. Sea-mats and corallines in general are 
plentiful. Numerous fragmentary Medusa (chiefly Aurelia 
aurita and Cyanea capillata ) strew the sands in company with 
Pleurobrachia , the parasitic Hyperice also being liberated from 
the former and swarming in the tide-pools. Anemones are com¬ 
mon, either perched inside shells or mixed with the debris ; and 
some of the rarer (such as Peachia hastata and the case-making 
Edioardsia ) lie freely in the pools. Alcyonium digitatum occurs 
in great profusion, both loose and attached to various shells, 
or on the leathery tubes of Sabella pavonia ; and the crevices 
of this zoophyte contain many specimens of Tritonia plebeia. 
Here and there are groups of large cockles ( Gardium echinatum ) 
exposing their pink feet through gaping valves; and in shallow 
pools the great whelk ( Buccinum undatum) spreads out its 
speckled fleshy disk. Multitudes of other univalves and bi¬ 
valves are scattered around, tufted with parasitic seaweeds and 
B 2 
