INTRODUCTION. 8 



valves of the commou 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 andiBotryl- 

 loides) are equally abundant. The coarse timnels of Thelepus 

 and Terebellce, the finer tubes of Sabdlaria^ and the white coils 

 of SerpulcR wind amongst the fasciculi ; 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 saccharina grow forests of 

 Ohelia gem'culata, 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 

 [EusyUis) . 



The chief representative of the sponges in these storms is 

 Halichondria panicea, though occasionally Chalina octdata is 

 equally abundant. The i-ugged masses of the former afford a 

 favourite lurking-place for Doris tuherculata, porcelain crabs, 

 and Lepidonoti; while in the general wreck it becomes 

 hispid with the stiff sharp spines of the sea-mice, common and 

 pm-ple heart urchins. Sea-mats and corallines in general are 

 plentiful. Numerous fragmentary Medusos (chiefly Aurelia 

 aurita and Cyanea ccqnllata) sti'ew the sands in company with 

 Pleurohrachia, the parasitic Hyperiw 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 PeacMa hastata and the case-making 

 Edwardsia) 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 ( Cardium echinatum) 

 exposing their pink feet through gaping valves ; and in shallow 

 pools the great whelk [Buccinuni undatum) spreads out its 

 speckled fleshy disk. Multitudes of other univalves and bi- 

 valves are scattered around, tufted with parasitic seaweeds and 



b2 



