Page:VCH Lancaster 1.djvu/144

A HISTORY OF LANCASHIRE not form a very inviting shore collecting ground. An abundant and varied shore fauna is only to be seen on a coast with rock pools, caves, seavi^eeds, and the Uke. Nowhere on the Lancashire Httoral do we find such conditions. Only here and there by taking advantage of the lowest spring tides do we find shore collecting at' all attractive. But even the ordinary beach, unattrac- tive as it may appear to the casual naturalist, yields a fair abundance of forms , if studied minutely. Thus Dr. Chaster has recorded no less than 150 species of Foraminifera and 140 species of Mollusca from the ordinary beach round Southport. At a few places we do find a shore fauna of considerable interest to the amateur zoologist, and I may give as an instance the shore in the vicinity of the Lancashire Fishery Research Station at Piel in the Barrow Channel. There we have on the one hand the sandy flats with occasional Zostera meadows on which small crustaceans abound, and on the other the ' Scars ' — rough stony ground with seaweed — which are exposed at low spring tides. Mussels, cockles, and periwinkles are of course abundant. In association with the former Molluscs we find the extraordinary Trematode Leucithodendrium somateria. Lev., which is the cause of the pearls so abundant in the mussels on the Piel foreshore. This animal, as Dr. H. Lyster Jameson has shown, passes through larval stages in the cockle and mussel, and in the latter becomes encysted and surrounded by the calcareous investment which becomes the pearl. The adult stage of the Trematode is found in the ' Scoter ' or Black Duck, which feeds on the mussel. Other Mollusca are abundant ; oysters are found, though not frequently ; Mytilus modiolus, the horse mussel, is frequently dredged in Barrow Channel ; ' hen pens ' {Mactra, Scrobicularia, and Tellind) may be got alive, and dead valves of the tapestry shell [Tapes), Nucula, the spiny cockle {Gardium echinatum), Psammobia, Donax, and others are numerous. The Clam {Mya arenarid) is quite common, and it often harbours the peculiar commensal Nemertine {Malacobdelld) in its mantle cavity. The whelks Buccinum undatum and Fusus anttquus, the dog whelk [Purpura lapillus), and the limpet [Patella vulgata) are of course abundant. Nudibranchs such as the sea slugs Doris and Eolis are present, and the gelatinous spawn of the former may always be got during the early summer. Cephalopods turn up ; Octopus is often got in the stake nets. Many Crustacea occur, such as the crabs Cancer, Carcinus, Portunus, Hyas, Stenorhynchus, and the hermit Pagurus. The beautiful fairy prawns Hippolyte varians, H. cranchii, H. fascigera, and H. pusiola may be got here in greater abundance than anywhere else in the Irish Sea. These animals are remarkable for the adaptation of their colour markings to that of the seaweeds on which they are found. This form of adaptation has been explained as one of ordinary protective resemblance, but the phenomenon is far from being a simple one. My sis neglecta, a common Schizopod, is extremely abun- dant. At least four genera of Pycnogonids may be collected — Nymphon, Pallene, Ammothea, and Anoplodactylus. Of the Echinoderms, the starfishes or ' crossfishes,' Asterias and Cribella, the Sun star [Solaster), and the urchin [Echinus) may be obtained alive, and dead tests of the heart urchin [Spatangus) and Echinocardium can be picked up. On this side of Morecambe Bay the common starfish has proved itself at times an intolerable nuisance, for many acres of the beach may be literally carpeted with these animals, which can be extremely destructive to the mussel beds. The starfish pulls apart the valves 92