MARINE ZOOLOGY of the mollusc by long continued traction by its tube feet, and then inserts its eversible pharynx between the valves and devours the soft body of the mussel. Anemones, of which Actinia is the commonest, used to be abundant on the piles of the old pier and may still be obtained from the rock pools. Simple and compound ascidians are very abundant on the same ground, Ascidia and the peculiar colonial Perophora on the stones, and the compound forms Botryllus and Amaroucium on the seaweeds. Worms are abundant, the commonest being the lugworm [Arenicola) , which forms an extensive bed, and Sabellaria, the agglomerated sand tubes of which form the hard sandy excres- cences known locally as ' knarrs.' Sabella, Serpula, 'Terebella, Pectinaria, and Onuphis (the latter rare) are other common tubicolous Polychstes, and the errant forms Phyllodoce, Scoloplus, Nereis, and Aphrodite may also be obtained. The two former worms deposit green and red albuminous cocoons containing their eggs, and these little masses, about the size of a grape, are very abun- dant here during the spring and in Morecambe Bay generally, where they were formerly supposed by fishermen to be the spawn of the plaice and flounder. Nemertines may also be taken, but they are not abundant. These are the common forms which can always be collected, but there are in addition hosts of amphipods and microcrustacea among the seaweeds and on the bottom deposits. Zoophytes are not uncommon. Incidentally it may be remarked that the mud flats yield a great abundance of diatoms. PLANKTON By plankton is understood the drifting pelagic microscopic life of the sea. This department of local marine zoology has received very considerable attention during the last twenty years. The late Mr. I. C. Thompson of Liverpool and the late Mr. R. L. Ascroft of Lytham both devoted much attention to this subject, and our knowledge of it is to a great extent the result of their joint labours. The former was one of the original members of the Lancashire Sea Fisheries Committee, and perhaps more than any other member of that Board encouraged and assisted in the scientific investiga- tion of sea fisheries questions. The uniformity of composition which one finds in oceanic plankton is wanting in that of inshore waters, where there is much greater variety in the collections made in different places and at different times in the year than in deep water far removed from land. At the beginning of the year the plank- ton of the Lancashire coastal waters is rather scanty. We find the Chjetogna- than worm Sagitta usually very abundant ; Copepods too, belonging to the geilera Acartia, Calanus, Pseudocalanus, Anomalocera, Isias, Euterpe, Oithona, and many others. Then about the beginning of March the pelagic eggs of teleostean fishes — the plaice, cod, haddock, whiting, dab, flounder, and many others — appear, and persist till about the beginning of May. Following these we often find the larvas of the same fishes, though it is rare to find these little creatures in the surface tow-nets. About this time of the year the larvae of various crustaceans appear in great abundance. The commonest is perhaps that of Balanus balanoides, the Barnacle or ' Scab.' I have seen a tow-net gathering containing practically nothing else than the nauplii of this Cirri- 93
